Systems and methods for analyte monitors

Abstract

The embodiments described herein include a device and a non-transitory computer readable medium. The device includes one or more processors, an analyte sensor, a communication module, and a memory. The processor is configured to generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a first time, generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a second time, calculate a correction parameter based on the analyte data corresponding to the first time and the analyte data corresponding to the second time, and perform a delay correction using at least the calculated correction parameter to obtain the monitored analyte level. The calculated correction parameter includes a delay time determined from the analyte data. The delay correction performed includes a linear correction model based on the calculated correction parameter.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 USC § 119(e) of U.S. Provisional Patent Application No. 63 / 295,654, filed December 31, 2021, which is incorporated herein by reference.

[0002] The subject matter of the present disclosure relates to systems and methods for analyte monitors, including systems and techniques involving calibration or correction performed during processing of analyte levels monitored from analyte sensors. [Background technology]

[0003] Detection of lactate or other analyte concentration levels in certain individuals using analyte sensors can be beneficial to their health. Lactate concentrations in blood or other bodily fluids are frequently used to determine an athlete's fitness level, prescribe sports training, and measure the effectiveness of training in preparation for competition.

[0004] Devices and systems have been developed for automatic in-vivo monitoring of analyte concentrations, such as lactate levels, in bodily fluids, such as the bloodstream or interstitial fluid (ISF). Some of these analyte level measurement devices are configured so that at least a portion of the device is positioned below the surface of the user's skin, for example, within the user's blood vessels or subcutaneous tissue. Analyte monitoring systems can include in-vivo monitoring systems that use a sensor placed at least partially subcutaneously to measure and store sensor data representative of analyte concentration levels over time.

[0005] Subcutaneous analyte sensors can measure the level of an analyte, such as lactate concentration, in the bloodstream or ISF, potentially with calibration or correction to the measured concentration of the analyte in the blood for further data processing or interpretation. For example, during exercise, lactate is produced in major muscles, exits the muscles to local venous drainage, and enters the systemic circulation, where lactate levels are detectable in the blood throughout the body within minutes. After a few minutes, lactate is detectable in the dermal ISF.

[0006] Because lactate levels change rapidly during exercise, a delay of several minutes between blood and ISF can result in different values. The blood-to-ISF delay time varies with each individual's sensor placement. This variability can be attributed, at least in part, to various factors, including, but not limited to, physiology, the distance from the sensor tail to the nearest capillary, and / or the diffusion of lactate through the ISF.

[0007] In vivo sensor calibration or correction by the user to account for differences between analyte concentrations in blood fluid and ISF often involves using blood samples and comparative testing methods and can produce better results matching blood analyte concentrations with sensor readings when changes in analyte concentration are minimal. Such calibration using capillary point-of-care blood samples can be difficult to achieve for analyte sensor lactate monitors, at least in part because resting lactate levels can be below 2.0 mM and near the low end of the measurement range. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Publication No. 2013 / 0150691 [Patent Document 2] U.S. Patent Application Publication No. 2021 / 0204841 [Patent Document 3] International Publication No. 2018 / 136898 [Patent Document 4] International Publication No. 2019 / 236850 [Patent Document 5] International Publication No. 2019 / 236859 [Patent Document 6] International Publication No. 2019 / 236876 [Patent Document 7] US Patent Publication No. 2020 / 0196919 [Patent Document 8] US Patent Publication No. 2016 / 0331283 [Patent Document 9] US Patent Publication No. 2018 / 0235520 [Patent Document 10] US Patent Publication No. 2014 / 0171771 [Patent Document 11] US Patent Publication No. 2010 / 00230285 [Patent Document 12] US Patent Publication No. 2019 / 0274598 Summary of the Invention [Problem to be solved by the invention]

[0009] Thus, an opportunity exists for devices and systems that can automatically and accurately perform correction or calibration functions for analyte sensors that monitor analytes, such as, but not limited to, lactate. Additionally, an opportunity exists for devices and systems that can accurately display monitored analyte levels, such as lactate concentrations, for a wide range of applications, including, but not limited to, medical, wellness, and fitness applications for users, and athletic training programs. [Means for solving the problem]

[0010] The objects and advantages of the disclosed subject matter will be set forth in the description which follows, and will be obvious from the description, or may be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the description and claims hereof, as well as the drawings.

[0011] To achieve these and other advantages and in accordance with the objectives of the presently disclosed subject matter, as embodied and broadly described, the presently disclosed subject matter includes an analyte monitoring device and a non-transitory computer-readable medium for monitoring an analyte. For example, the device can include one or more processors. The one or more processors can be configured to receive a signal from an analyte sensor. The analyte sensor can be, for example, a lactate sensor. At least a portion of the analyte sensor is positioned in contact with the bodily fluid. The one or more processors are also configured to determine a peak signal width of a signal received from the analyte sensor over a period of time. Additionally, the one or more processors are configured to determine a lactate concentration in the bodily fluid based in part on the peak signal width of the received signal.

[0012] In accordance with one aspect of the presently disclosed subject matter, an analyte monitor device in accordance with the presently disclosed subject matter includes one or more processors, an analyte sensor, a communications module, and one or more memories communicatively coupled to the one or more processors, the analyte sensor, and the communications module, wherein the one or more processors are configured to generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a first time, generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a second time, calculate a correction parameter based on the analyte data corresponding to the first time and the analyte data corresponding to the second time, and perform a delay correction using at least the calculated correction parameter to obtain the monitored analyte level.

[0013] Additionally or alternatively, the processor may calculate a rate of change of the monitored analyte level based on analyte data measured by the analyte sensor. The processor may perform a lag correction on the monitored analyte level during the user's exercise period. As embodied herein, the exercise period includes a period of high-intensity exercise. The analyte sensor is subcutaneously inserted into the user's bodily fluid. As embodied herein, the bodily fluid may be blood fluid or interstitial fluid (ISF).

[0014] Additionally or alternatively, the processor may perform the correction using correction parameters including a delay time calculated based on the first time and the second time. The delay correction may be performed using a linear correction model. The delay correction performed may be equal to an intercept added to the product of the calculated delay time multiplied by the rate of change of the monitored analyte level based on the analyte data measured by the analyte sensor. As embodied herein, the intercept may be a value dependent on the analyte sensor.

[0015] Additionally or alternatively, the processor may perform delay correction, including correcting for a delay between a change in the monitored analyte level in the interstitial fluid and the monitored analyte level in the blood. As embodied herein, the analyte monitor device may further include a display configured to receive and display the monitored analyte level.

[0016] In accordance with another aspect of the presently disclosed subject matter, a corresponding non-transitory computer-readable medium is disclosed. The computer-readable medium includes instructions for generating analyte data indicative of a monitored analyte level measured by an analyte sensor corresponding to a first time, instructions for generating analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a second time, instructions for calculating a correction parameter based on the analyte data corresponding to the first and second times, and instructions for performing a delay correction on the monitored analyte level using at least the calculated correction parameter. Additionally or alternatively, the computer-readable medium may include corresponding features of a processor according to the presently disclosed subject matter.

[0017] It is to be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further explanation of the presently disclosed subject matter. The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to illustrate and provide a further understanding of the methods and systems of the disclosed subject matter. Together with the description, these drawings serve to explain the principles of the disclosed subject matter.

[0018] The details of the subject matter presented herein, both as to structure and operation, will be apparent from examination of the accompanying drawings, in which like reference numerals refer to like parts and in which: [Brief explanation of the drawings]

[0019] [Figure 1A] 1 is a system schematic diagram of a sensor applicator, a reader device, a monitor system, a network, and a remote system. [Figure 1B] FIG. 1 illustrates the operating environment of an exemplary analyte monitor system for use with the technology described herein. [Figure 2A] FIG. 2 is a block diagram illustrating an exemplary embodiment of a reader device. [Figure 2B] FIG. 1 is a block diagram illustrating an example data receiving device for communicating with a sensor in accordance with an example embodiment of the disclosed subject matter. [Figure 2C] FIG. 1 is a block diagram illustrating an exemplary embodiment of a sensor control device. [Figure 2D] FIG. 1 is a block diagram illustrating an exemplary embodiment of a sensor control device. [Figure 2E] FIG. 1 is a block diagram illustrating an exemplary analyte sensor according to an exemplary embodiment of the disclosed subject matter. [Figure 3A] FIG. 10 is a close-up perspective view depicting an exemplary embodiment in which a user prepares a tray for assembly. [Figure 3B] FIG. 10 is a side view depicting an exemplary embodiment in which a user prepares the applicator device for assembly. [Figure 3C] FIG. 10 is a close-up perspective view depicting an exemplary embodiment in which a user inserts an applicator device into a tray during assembly. [Figure 3D] FIG. 10 is a close-up perspective view depicting an exemplary embodiment in which a user removes the applicator device from a tray during assembly. [Figure 3E] FIG. 10 is a close-up perspective view depicting an exemplary embodiment in which a patient applies a sensor using an applicator device. [Figure 3F] FIG. 1 is a close-up perspective view depicting an exemplary embodiment of a patient with an attached sensor and an applicator device in use. [Figure 4A] 1 is a side view depicting an exemplary embodiment of an applicator device coupled to a cap. [Figure 4B] FIG. 10 is a side perspective view depicting an exemplary embodiment of an applicator device and cap separated. [Figure 4C] 1 is a perspective view depicting an exemplary embodiment of the distal end of an applicator device and electronics housing. [Figure 4D] FIG. 1 is a top perspective view of an exemplary applicator device in accordance with the disclosed subject matter. [Figure 4E] FIG. 4E is a bottom perspective view of the applicator device of FIG. 4D. [Figure 4F] FIG. 4E is an exploded view of the applicator device of FIG. 4D. [Figure 4G] FIG. 4E is a side cutaway view of the applicator device of FIG. 4D. [Figure 5] FIG. 1 is a close-up perspective view depicting an exemplary embodiment of a tray with a sterilization lid attached thereto. [Figure 6A] 1 is a close-up perspective cutaway view depicting an exemplary embodiment of a tray having a sensor delivery component. [Figure 6B] FIG. 1 is a close-up perspective view depicting a sensor delivery component. [Figure 7A] FIG. 1 is an isometric exploded top view of an exemplary sensor control device. [Figure 7B] FIG. 1 is an isometric exploded bottom view of an exemplary sensor control device. [Figure 8A] FIG. 12 is a diagram of an assembly of a body worn device including an integrated connector for a sensor assembly. [Figure 8B] FIG. 1 is a cross-sectional view of a body worn device including an integrated connector for a sensor assembly. [Figure 8C] FIG. 1 is a cross-sectional view of a body worn device including an integrated connector for a sensor assembly. [Figure 9A] 2D is a side view of the exemplary embodiment of the sensor applicator of FIG. 1A coupled with the cap of FIG. 2C. [Figure 9B] 2D is a cross-sectional side view of an exemplary embodiment of the sensor applicator of FIG. 1A coupled with the cap of FIG. 2C. [Figure 10A] FIG. 10 is an isometric view of another exemplary sensor control device. [Figure 10B] FIG. 10 is a side view of another exemplary sensor control device. [Figure 11A] 10A-10B. FIG. 10B is a cross-sectional side view illustrating the assembly of a sensor applicator with the sensor control device of FIGS. [Figure 11B] 10A-10B are cross-sectional side views illustrating the assembly of a sensor applicator and the sensor control device of FIGS. 10A-10B. [Figure 11C] 10A-10B are cross-sectional side views illustrating the assembly of a sensor applicator and the sensor control device of FIGS. 10A-10B. [Figure 12A]10A-10B are cross-sectional side views illustrating the assembly and disassembly of an exemplary embodiment of the sensor applicator and sensor control device of FIGS. 10A-10B. [Figure 12B] 10A-10B are cross-sectional side views illustrating the assembly and disassembly of an exemplary embodiment of the sensor applicator and sensor control device of FIGS. 10A-10B. [Figure 12C] 10A-10B are cross-sectional side views illustrating the assembly and disassembly of an exemplary embodiment of the sensor applicator and sensor control device of FIGS. 10A-10B. [Figure 13A] 1 is a cross-sectional view depicting an exemplary embodiment of an applicator during a deployment stage. [Figure 13B] 1 is a cross-sectional view depicting an exemplary embodiment of an applicator during a deployment stage. [Figure 13C] 1 is a cross-sectional view depicting an exemplary embodiment of an applicator during a deployment stage. [Figure 13D] 1 is a cross-sectional view depicting an exemplary embodiment of an applicator during a deployment stage. [Figure 13E] 1 is a cross-sectional view depicting an exemplary embodiment of an applicator during a deployment stage. [Figure 13F] 1 is a cross-sectional view depicting an exemplary embodiment of an applicator during a deployment stage. [Figure 14] 1 is a graph depicting an example of in vitro sensitivity of an analyte sensor. [Figure 15] 1A-1C illustrate exemplary operational states of a sensor according to an exemplary embodiment of the disclosed subject matter. [Figure 16] 10A-10D illustrate exemplary operational and data flows for wireless programming of a sensor in accordance with the disclosed subject matter. [Figure 17] FIG. 1 illustrates an example data flow for secure data exchange between two devices in accordance with the disclosed subject matter. [Figure 18] FIG. 1 illustrates the change in blood lactate levels in different training zones in an athlete. [Figure 19] FIG. 10 illustrates different response delays to changes in blood lactate for different analyte sensors located proximate to a subcutaneous insertion site in the same user. [Figure 20] 1 is a flow chart illustrating an example process for performing sensor calibration in an example analyte sensor system in accordance with the subject matter of the present disclosure. [Figure 21] FIG. 10 illustrates the different response delays to changes in blood lactate for different analyte sensors in the same user proximate to a subcutaneous insertion site after correction. [Figure 22] FIG. 10 illustrates lactate level changes during high intensity exercise for determining correction parameters. DETAILED DESCRIPTION OF THE INVENTION

[0020] Reference will now be made to various exemplary embodiments of the presently disclosed subject matter, which are illustrated in the accompanying drawings. The structure and corresponding method of operation of the presently disclosed subject matter will now be described in conjunction with a detailed system description.

[0021] In accordance with one aspect of the presently disclosed subject matter, an analyte monitor device in accordance with the presently disclosed subject matter includes one or more processors, an analyte sensor, a communications module, and one or more memories communicatively coupled to the one or more processors, the analyte sensor, and the communications module, wherein the one or more processors are configured to generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a first time, generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a second time, calculate a correction parameter based on the analyte data corresponding to the first time and the analyte data corresponding to the second time, and perform delay correction using at least the calculated correction parameter to obtain the monitored analyte level.

[0022] Additionally or alternatively, the processor may calculate a rate of change of the monitored analyte level based on analyte data measured by the analyte sensor. The processor may perform a lag correction on the monitored analyte level during the user's exercise period. As embodied herein, the exercise period includes a period of high-intensity exercise. The analyte sensor is subcutaneously inserted into the user's bodily fluid. As embodied herein, the bodily fluid may be blood fluid or interstitial fluid (ISF).

[0023] Additionally or alternatively, the processor may perform the correction using correction parameters including a delay time calculated based on the first time and the second time. The delay correction may be performed using a linear correction model. The delay correction performed may be equal to an intercept added to the product of the calculated delay time multiplied by the rate of change of the monitored analyte level based on the analyte data measured by the analyte sensor. As embodied herein, the intercept may be a value dependent on the analyte sensor.

[0024] Additionally or alternatively, the processor may perform delay correction, including correcting for a delay between a change in the monitored analyte level in the interstitial fluid and a change in the monitored analyte level in the blood. As embodied herein, the analyte monitor device may further include a display configured to receive and display the monitored analyte level.

[0025] In accordance with another aspect of the presently disclosed subject matter, a corresponding non-transitory computer-readable medium is disclosed, the non-transitory computer-readable medium including instructions for generating analyte data indicative of a monitored analyte level measured by an analyte sensor corresponding to a first time, instructions for generating analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a second time, instructions for calculating a correction parameter based on the analyte data corresponding to the first time and the second time, and instructions for performing a delay correction on the monitored analyte level using at least the calculated correction parameter. Additionally or alternatively, the computer-readable medium may include corresponding features of a processor according to the presently disclosed subject matter.

[0026] The systems and methods provided herein can be used in conjunction with sensors used in analyte monitoring systems for purposes such as, but not limited to, wellness, fitness, dietary therapy, research, information, or any purpose involving longitudinal analyte sensing. As used herein, "analyte sensor" or "sensor" can refer to any device capable of accepting sensor information from a user, including, by way of example only, a temperature sensor, a blood pressure sensor, a pulse or heart rate sensor, a glucose level sensor, an analyte sensor, a physical activity sensor, a physical movement sensor, or any other sensor for collecting physical or biometric information. Analytes measured by an analyte sensor can include, by way of example only, glucose, ketones, lactate, oxygen, hemoglobin A1C, albumin, alcohol, alkaline phosphatase, alanine transaminase, aspartate aminotransferase, bilirubin, blood urea nitrogen, calcium, carbon dioxide, chloride, creatinine, hematocrit, lactate, magnesium, oxygen, pH, phosphorus, potassium, sodium, total protein, uric acid, and the like. Objects and advantages of the presently disclosed subject matter will be set forth in the following and will be apparent from the following description. Additional advantages of the presently disclosed subject matter will be realized and obtained by the methods, apparatus, and devices particularly pointed out in the specification and claims hereof, as well as the appended drawings.

[0027] Generally, embodiments of the present disclosure include systems, devices, and methods for use of an analyte sensor insertion applicator for use with an in-vivo analyte monitor system. The applicator can be provided to a user in a sterile package with an electronics housing of a sensor control device enclosed therein. According to some embodiments, a structure separate from the applicator, such as a container, can also be provided to a user in a sterile package with a sensor module and a sharps module enclosed therein. The user can couple the sensor module to the electronics housing and couple the sharps to the applicator through an assembly process that includes inserting the applicator into the container in a specified manner. In other embodiments, the applicator, sensor control device, sensor module, and sharps module can be provided in a single package. The applicator can be used to position the sensor control device on the human body with the sensor in contact with the wearer's bodily fluids. The embodiments provided herein are improvements that reduce the likelihood of the sensor being improperly inserted, damaged, or eliciting an adverse physiological response. Other improvements and advantages are also provided. Various configurations of these devices are described in detail using exemplary embodiments only.

[0028] Additionally, many embodiments include in-vivo analyte sensors that are structurally configured such that at least a portion of the sensor is or can be positioned on the body of a user to obtain information regarding at least one analyte in the body. However, it should be noted that the embodiments disclosed herein can be used with in-vivo analyte monitoring systems that incorporate extracorporeal functionality, as well as purely extracorporeal or ex vivo analyte monitoring systems, including completely non-invasive systems.

[0029] Furthermore, with respect to each and every embodiment of the methods disclosed herein, systems and devices having the functionality to perform each of these embodiments are encompassed within the scope of the present disclosure. For example, sensor control device embodiments are disclosed, which can have one or more sensors, analyte monitor circuitry (e.g., analog circuitry), memory (e.g., for storing instructions), power sources, communication circuitry, transmitters, receivers, processors, and / or controllers (e.g., for executing instructions) that can perform or facilitate the performance of any and all method steps. These sensor control device embodiments can be used to, and can have the functionality to, perform steps performed by the sensor control device from any and all of the methods described herein.

[0030] Additionally, the systems and methods provided herein can be used in conjunction with sensors used in analyte monitoring systems, such as, but not limited to, for wellness, fitness, dietary, research, information, or any purpose involving longitudinal analyte sensing. As used herein, "analyte sensor" or "sensor" can refer to any device capable of accepting sensor information from a user, including, by way of example only, a temperature sensor, a blood pressure sensor, a pulse or heart rate sensor, a glucose level sensor, an analyte sensor, a physical activity sensor, a physical movement sensor, or any other sensor for collecting physical or biometric information. Analytes measured by an analyte sensor can include, by way of example only, glucose, ketones, lactate, oxygen, hemoglobin A1C, albumin, alcohol, alkaline phosphatase, alanine transaminase, aspartate aminotransferase, bilirubin, blood urea nitrogen, calcium, carbon dioxide, chloride, creatinine, hematocrit, lactate, magnesium, oxygen, pH, phosphorus, potassium, sodium, total protein, uric acid, and the like.

[0031] As mentioned above, certain embodiments of systems, devices, and methods are described herein that provide improved assembly and use of dermal sensor insertion devices for use with in-vivo analyte monitoring systems. In particular, certain embodiments of the present disclosure provide improved sensor insertion methods for in-vivo analyte monitoring systems, and are specifically designed to prevent premature retraction of the insertion tip during the sensor insertion process. Some embodiments include, for example, a dermal sensor insertion mechanism with a high firing rate and slow tip retraction. In other embodiments, the tip retraction mechanism can be exercise-activated, such that the tip does not retract until the user pulls the applicator away from the skin. As a result, these embodiments can reduce the likelihood of premature removal of the insertion tip during the sensor insertion process, reduce the likelihood of incorrect sensor insertion, and reduce the likelihood of damaging the sensor during the sensor insertion process, to name a few advantages. Some embodiments of the present disclosure also enable improved insertion tip modules that account for the small scale of dermal sensors and the relatively shallow insertion path present in a subject's dermis. Additionally, some embodiments of the present disclosure are designed to prevent undesired axial and / or rotational movement of applicator components during sensor insertion. These embodiments can therefore reduce the likelihood of capillary disruption resulting in instability of the positioned dermal sensor, irritation at the insertion site, damage to surrounding tissue, and contamination of skin fluids with blood, to name a few advantages. Furthermore, to mitigate inaccurate sensor readings that may be caused by trauma at the insertion site, some embodiments of the present disclosure can reduce the distal needle penetration depth relative to the sensor tip during insertion.

[0032] However, before describing the above aspects of the embodiments in detail, it is desirable to first describe examples of devices and their operation that may be present, for example, in an in vivo analyte monitor system, all of which may be used in the embodiments described herein.

[0033] Various types of in-vivo analyte monitor systems exist. A "continuous analyte monitor" system (or "continuous glucose monitor" system), for example, can transmit data continuously, e.g., automatically according to a schedule, from the sensor control device to the reader device without requiring acknowledgment. As another example, an "intermittent analyte monitor" system (or "intermittent glucose monitor" system, or simply "intermittent" system) can transmit data from the sensor control device using scanning by the reader device or, optionally, near-field communication (NFC) protocols or radio frequency identification (RFID) protocols, etc. In-vivo analyte monitor systems can operate without the need for fingerstick calibration.

[0034] In vivo analyte monitor systems can be distinguished from "ex vivo" systems, which generally include a measurement device that contacts a biological sample outside the body (or "ex vivo") and has a port for accepting an analyte test strip that carries a user's bodily fluid and can be analyzed to determine the user's blood glucose level.

[0035] An in-vivo monitoring system may include a sensor that contacts a user's bodily fluid while positioned in vivo and senses the analyte level contained therein. The sensor may be part of a sensor control device that resides on the user's body, the sensor control device including the electronics and power source that enable and control the analyte sensing. Sensor control devices and variations thereof may be referred to as "sensor control units," "body-worn electronics" devices or units, "body-worn" devices or units, or "sensor data communication" devices or units, to name a few.

[0036] An in-vivo monitoring system may include a device that accepts sensed analyte data from the sensor control device and processes and / or displays it to a user in any number of forms. This device and variations thereof may be referred to as a "handheld reader device," "reader device," (or simply "reader"), "handheld electronic device" (or simply "handheld"), "portable data processing" device or unit, "data receiver," "receiver" device or unit (or simply "receiver"), or "remote" device or unit, to name a few. Other devices, such as personal computers, have also been used with or incorporated into in-vivo or in-vitro monitoring systems.

[0037] FIG. 1A is a conceptual diagram illustrating an exemplary embodiment of an analyte monitoring system 100 including a sensor applicator 150, a sensor control device 102, and a reader device 120. In this case, the sensor applicator 150 can be used to deliver the sensor control device 102 to a monitoring location on a user's skin, where the analyte sensor 110 is held stationary for a period of time by an adhesive patch 105. The sensor control device 102, described in more detail in FIGS. 2B and 2C, can communicate with the reader device 120 over a communication path 140 using wired or wireless technology. Exemplary wireless protocols include Bluetooth, Bluetooth Low Energy (such as BLE, BTLE, or Bluetooth Smart), Near Field Communication (NFC), and others. A user can monitor applications installed in memory on the reader device 120 using a screen 122 and input 121, and can recharge the device's battery using a power port 123. Further details regarding the reader device 120 are discussed below with respect to FIG. 2A . The reader device 120 can communicate with a local computer system 170 over a communication path 141 using wired or wireless technology. The local computer system 170 can include one or more of a laptop, desktop, tablet, phablet, smart phone, set-top box, video game console, or other computing device, and the wireless communication can include any of several applicable wireless networking protocols, including Bluetooth, Bluetooth Low Energy (BTLE), Wi-Fi, or others. The local computer system 170 can communicate with the network 190 over a communication path 143 using wired or wireless technology, as described above, in a manner similar to the manner in which the reader device 120 can communicate with the network 190 over communication path 142. The network 190 can be any of several networks, such as private and public networks, and local or wide area networks.The trusted computer system 180 may include a server, may provide authentication services and secure data storage, and may communicate with the network 190 through a communication path 144 using wired or wireless technology.

[0038] FIG. 1B illustrates the operating environment of an analyte monitoring system 100a capable of embodying the techniques described herein. The analyte monitoring system 100a may include a system comprised of components designed to provide monitoring of a parameter, such as an analyte level in a human or animal, or may enable other operations based on the configuration of the various components. As embodied herein, the system may include a low-power analyte sensor 110, or simply a “sensor,” worn by a user or attached to the body from which information is being collected. As embodied herein, the analyte sensor 110 may be a sealed, disposable device having a predetermined useful lifespan (e.g., about 1 day, about 14 days, about 30 days, etc.). The sensor 110 may be applied to the skin of a user's body and may remain adhered for the duration of the sensor's lifespan, or may be designed to remain functional when selectively detached and reapplied. The low power analyte monitor system 100a may further include a data reading device 120 or a general-purpose data receiving device 130 configured as described herein to facilitate retrieval and transmission of data, including analyte data, from the analyte sensor 110.

[0039] As embodied herein, the analyte monitoring system 100a may include a software or firmware library or application provided by a third party, for example, through a remote application server 150 or an application point-of-sale server 160, and embedded within a general-purpose hardware device 130, such as a mobile phone, tablet, personal computing device, or other similar computing device capable of communicating with the analyte sensor 110 over a communications link. The general-purpose hardware may further include an embedded device, including, but not limited to, an insulin pump or insulin pen having an embedded library configured to communicate with the analyte sensor 110. While the illustrated embodiment of the analyte monitoring system 100a includes only one of each of the illustrated devices, the present disclosure contemplates that the analyte monitoring system 100a may incorporate multiple components through which the components interact. By way of example and not limitation, as embodied herein, the data reading device 120 and / or the general-purpose data receiving device 130 may include multiple components. As embodied herein, multiple data receiving devices 130 may communicate directly with the sensor 110 as described herein. Additionally or alternatively, a data receiving device 130 may communicate with ancillary data receiving devices 130 to provide analyte data or a visual representation or analytical results thereof for ancillary display to a user or other authorized interested party.

[0040] 2A is a block diagram illustrating an exemplary embodiment of a reader device configured as a smart phone. In this case, reader device 120 may include display 122, input components 121, and processing core 206 including a communication processor 222 coupled to memory 223 and an application processor 224 coupled to memory 225. Also included may be separate memory 230, an RF transceiver 228 having an antenna 229, and a power supply 226 having a power management module 238. Additionally, a multi-function transceiver 232 capable of communicating via Wi-Fi, NFC, Bluetooth, BTLE, and GPS using antenna 234 may be included. As will be appreciated by those skilled in the art, these components are electrically and communicatively coupled in a manner to create a functional device.

[0041] For purposes of illustration and not limitation, reference is made to the exemplary embodiment of a data receiving device 120 shown in FIG. 2B for use with the subject matter of the present disclosure. The data receiving device 120 and associated general-purpose data receiving device 130 include components germane to the discussion of the analyte sensor 110 and its operation, and may include additional components. In certain embodiments, the data receiving device 120 and general-purpose data receiving device 130 may be or include components provided by third parties, and are not necessarily limited to including devices manufactured by the same manufacturer as the manufacturer of the sensor 110.

[0042] 2B , the data receiving device 120 includes an ASIC 4000 that includes a microcontroller 4010, a memory 4020, and storage 4030 communicatively coupled to a communication module 4040. Power for the components of the data receiving device 120 may be provided by a power module 4050, which may include a rechargeable battery as embodied herein. The data receiving device 120 may further include a display 4070 to facilitate review of analyte data received from the analyte sensor 110 or other devices (e.g., the user device 140 or the remote application server 150). The data receiving device 120 may include separate user interface components (e.g., physical keys, a light sensor, a microphone, etc.).

[0043] The communications module 4040 may include a BLE module 4041 and an NFC module 4042. The data receiving device 120 may be configured to wirelessly couple to the analyte sensor 110 and send commands to and receive data from the analyte sensor 110. As embodied herein, the data receiving device 120 may be configured to operate as an NFC scanner and a BLE endpoint through a particular module of the communications module 4040 (e.g., the BLE module 4042 or the NFC module 4043) with respect to the analyte sensor 110 described herein. For example, the data receiving device 120 may issue commands to the analyte sensor 110 (e.g., an activation command for the sensor's data broadcast mode, a pairing command for identifying the data receiving device 120) using a first module of the communications module 4040 and send and receive data to and from the analyte sensor 110 using a second module of the communications module 4040. The data receiving device 120 may be configured for communication with the user device 140 through a universal serial bus (USB) module 4045 of the communications module 4040.

[0044] As another example, the communications module 4040 may include, for example, a cellular radio module 4044. The cellular radio module 4044 may include one or more wireless transceivers for communicating with broadband cellular networks, including, but not limited to, third-generation (3G), fourth-generation (4G), and fifth-generation (5G) networks. Additionally, the communications module 4040 of the data receiving device 120 may include a Wi-Fi radio module 4043 for communicating with wireless local area networks according to one or more of the IEEE 802.11 standards (e.g., 802.11a, 802.11b, 802.11g, 802.11n (also known as Wi-Fi 4), 802.11ac (also known as Wi-Fi 5), and 802.11ax (also known as Wi-Fi 6)). Using the cellular wireless module 4044 or the Wi-Fi wireless module 4043, the data receiving device 120 can communicate with a remote application server 150 to receive analyte data, or can provide updates or input received from a user (e.g., through one or more user interfaces). Although not illustrated, the communication module 5040 of the analyte sensor 120 can also include a cellular wireless module or a Wi-Fi wireless module.

[0045] As embodied herein, the on-board storage 4030 of the data receiving device 120 can store analyte data received from the analyte sensor 110. Furthermore, the data receiving device 120, the general-purpose data receiving device 130, or the user device 140 can be configured to communicate with a remote application server 150 over a wide area network. As embodied herein, the analyte sensor 110 can provide data to the data receiving device 120 or the general-purpose data receiving device 130. The data receiving device 120 can transmit these data to the user computing device 140. Furthermore, the user computing device 140 (or the general-purpose data receiving device 130) can transmit these data to the remote application server 150 for processing and analysis.

[0046] As embodied herein, the data receiving device 120 may further include sensing hardware 4060 similar to or enhanced from the sensing hardware 5060 of the analyte sensor 110. In certain embodiments, the data receiving device 120 may be configured to interface with the analyte sensor 110 and act based on analyte data received therefrom. As an example, if the analyte sensor 110 is a glucose sensor, the data receiving device 120 may be or include an insulin pump or an insulin injection pen. In conjunction therewith, the interchangeable device 130 may adjust insulin dosages for the user based on glucose values ​​received from the analyte sensor.

[0047] 2C and 2D are block diagrams illustrating an exemplary embodiment of a sensor control device 102 having an analyte sensor 110 and sensor electronics 160, which may contain most of the processing functionality for rendering final result data suitable for display to a user. FIG. 2C shows a single semiconductor chip 161, which may be a custom application-specific integrated circuit (ASIC). Within the ASIC 161, certain high-level functional units are shown, including an analog front-end (AFE) 162, a power management (or control) circuit 164, a processor 166, and a communications circuit 168 (which may be embodied as a transmitter, receiver, transceiver, passive circuitry, or other communications protocol). While both the AFE 162 and the processor 166 are used as analyte monitoring circuitry in this embodiment, in other embodiments, either circuitry may perform the analyte monitoring function. The processor 166 may include one or more processors, microprocessors, controllers, and / or microcontrollers, each of which may be a separate chip or distributed among (and be part of) several different chips.

[0048] Also included within ASIC 161 is memory 163, which may be shared by various functional units present within ASIC 161 or distributed among two or more of these functional units. Memory 163 may be a separate chip. Memory 163 may be volatile and / or non-volatile memory. In this embodiment, ASIC 161 is coupled to a power source 170, which may be a coin cell battery or the like. AFE 162 interfaces with and accepts measurement data from in-vivo analyte sensor 110 and outputs these data in digital form to processor 166, which further processes these data to provide final result glucose individual values ​​and glucose trend values, etc. These data may then be provided to communication circuitry 168 for transmission via antenna 171 to, for example, reader device 120 (not shown), where minimal additional processing by a resident software application is required to display the data.

[0049] 2D is similar to FIG. 2C but includes two separate semiconductor chips 162 and 174, which can be packaged together or separately. In this case, AFE 162 resides on ASIC 161. Processor 166 is integrated with power management circuitry 164 and communications circuitry 168 on chip 174. AFE 162 includes memory 163, and chip 174 includes memory 165, which can be isolated or distributed within it. In one exemplary embodiment, AFE 162 is combined with power management circuitry 164 and processor 166 on one chip, while communications circuitry 168 is on a separate chip. In another exemplary embodiment, both AFE 162 and communications circuitry 168 are on one chip, and processor 166 and power management circuitry 164 are on another chip. It should be noted that other chip combinations are possible, including three or more chips each performing a separate function as described, or each sharing one or more functions to achieve fail-safe redundancy.

[0050] For purposes of illustration and not limitation, reference is made to an exemplary embodiment of an analyte sensor 110 for use with the presently disclosed subject matter shown in Figure 2E, which illustrates a block diagram of an exemplary analyte sensor 110 according to an exemplary embodiment compatible with the security architecture and communication schemes described herein.

[0051] As embodied herein, the analyte sensor 110 may include an application specific integrated circuit ("ASIC") 5000 communicatively coupled to a communications module 5040. The ASIC 5000 may include a microcontroller core 5010, an on-board memory 5020, and a storage memory 5030. The storage memory 5030 may store data used for authentication and encryption security architectures. The storage memory 5030 may store programming instructions for the sensor 110. As embodied herein, certain communications chipsets (e.g., an NFC transceiver 5025) may be embedded within the ASIC 5000. The ASIC 5000 may receive power from a power module 5050, such as an on-board battery, or from NFC pulses. The storage memory 5030 of the ASIC 5000 may be programmed to include information such as an identifier for the sensor 110 for identification and tracking purposes. The storage memory 5030 may be programmed with configuration or calibration parameters for use by the sensor 110 and its various components. The storage memory 5030 may include rewritable memory or one-time programming (OTP) memory that can be updated using techniques described herein to extend the usefulness of the sensor 110.

[0052] As embodied herein, the communication module 5040 of the sensor 100 may be or include one or more modules for supporting communication of the analyte sensor 110 with other devices in the analyte monitoring system 100. By way of example only and not limitation, the exemplary communication module 5040 may include a Bluetooth Low Energy ("BLE") module 5041, where Bluetooth Low Energy ("BLE") is used throughout this disclosure to refer to a short-range communication protocol optimized for easy Bluetooth device pairing for end users. The communication module 5040 may transmit and receive data and instructions by interacting with a similarly capable communication module in the data receiving device 120 or user device 140. The communication module 5040 may include additional or alternative chipsets for use with similar short-range communication schemes, such as, for example, the IEEE 802.15 protocol, personal area networks according to the IEEE 802.11 protocol, or infrared communication according to the Infrared Data Association (IrDA) standard.

[0053] To perform its functions, the sensor 100 may further include sensing hardware 5060 appropriate for those functions. As embodied herein, the sensing hardware 5060 may include an analyte sensor placed transcutaneously or subcutaneously in contact with the subject's bodily fluid. The analyte sensor may generate sensor data including values ​​corresponding to one or more analyte levels present in the bodily fluid.

[0054] The components of the sensor control device 102 are available to the user in multiple packages that require final assembly by the user before delivery to the appropriate user location. Figures 3A-3D depict an exemplary embodiment of a user assembly process for the sensor control device 102, including preparation of the separate components before combining the components to prepare the sensor for delivery. Figures 3E-3F depict an exemplary embodiment of delivery of the device 102 to the appropriate user location by selecting the appropriate delivery location and attaching the sensor control device 102 to that location.

[0055] 3A is a close-up perspective view depicting an exemplary embodiment in which a user provides a container 810, in this case configured as a tray for the assembly process (although other packaging can be used). The user can accomplish this preparation by removing the lid 812 from the tray 810 to expose the platform 808, for example, by peeling the non-adhesive portion of the lid 812 from the tray 810 so that the adhesive portion of the lid 812 is removed. Removal of the lid 812 can be suitable in various embodiments as long as the platform 808 is sufficiently exposed within the tray 810. The lid 812 can then be set aside.

[0056] 3B is a side view depicting an exemplary embodiment in which a user prepares applicator device 150 for assembly. Applicator device 150 may be provided in a sterile package sealed by cap 708. Preparing applicator device 150 may include separating housing 702 from cap 708 to expose sheath 704 (FIG. 3C). This separation may be accomplished by unscrewing (or otherwise detaching) cap 708 from housing 702. Cap 708 may then be set aside.

[0057] 3C is a close-up perspective view depicting an exemplary embodiment in which a user inserts applicator device 150 into tray 810 during assembly. First, a user can insert sheath 704 into platform 808 inside tray 810 after housing orientation feature 1302 (or slot or recess) and tray orientation feature 924 (abutment or detent) are aligned. Inserting sheath 704 into platform 808 temporarily unlocks sheath 704 from housing 702, and also temporarily unlocks platform 808 from tray 810. Now, removal of applicator device 150 from tray 810 will result in the same condition as before the initial insertion of applicator device 150 into tray 810 (i.e., the process can be reversed or interrupted at this point and repeated without further repercussions).

[0058] During distal advancement of housing 702, sheath 704 maintains its position relative to housing 702 within platform 808 and can mate with platform 808, advancing platform 808 distally relative to tray 810. This unlocks and collapses platform 808 within tray 810. Sheath 704 contacts and disengages a locking feature (not shown) within tray 810, thereby unlocking sheath 704 from housing 702 and preventing it from moving (relatively) while housing 702 distally advances platform 808. At the end of advancement of housing 702 and platform 808, sheath 704 is permanently unlocked from housing 702. At the end of distal advancement of housing 702, a tip and sensor (not shown) within tray 810 can mate with an electronics housing (not shown) within housing 702. The operation and interaction of applicator device 150 and tray 810 is described in further detail below.

[0059] 3D is a close-up perspective view depicting an exemplary embodiment in which a user removes applicator device 150 from tray 810 during assembly. A user can remove applicator 150 from tray 810 by advancing housing 702 proximally relative to tray 810 or by other movement that has the same end effect as decoupling applicator 150 and tray 810. Applicator device 150 is removed with sensor control device 102 (point, sensor, electronics) (not shown) fully assembled therein and positioned for delivery.

[0060] 3E is a close-up perspective view depicting an exemplary embodiment in which a patient uses applicator device 150 to apply sensor control device 102 to a target area of ​​skin, for example, on the abdomen or other suitable location. Advancing housing 702 collapses sheath 704 distally therein, applying the sensor to the target location such that the adhesive layer on the bottom surface of sensor control device 102 adheres to the skin. The tip automatically retracts when housing 702 is fully advanced, while the sensor (not shown) is left in place to measure the analyte level.

[0061] 3F is a close-up perspective view depicting an exemplary embodiment of a patient with the sensor control device 102 in an application position. The user can then remove the applicator 150 from the application site.

[0062] 3A-3F and further described elsewhere herein can reduce or eliminate the possibility of accidental damage, permanent deformation, or incorrect assembly of applicator components compared to prior art systems. Because applicator housing 702 directly engages platform 808 while sheath 704 is unlocked, rather than indirectly engaging through sheath 704, the relatively angular configuration between sheath 704 and housing 702 does not result in damage or permanent deformation of arms or other components. This reduces the likelihood of relatively high forces being required during assembly (as with prior devices), thereby reducing the likelihood of user assembly failure.

[0063] Figure 4A is a side view depicting an exemplary embodiment of applicator device 150 coupled to screw cap 708. This view is an example of how applicator 150 may be shipped and received by a user prior to assembly with a sensor by the user. Figure 4B is a side perspective view depicting applicator 150 and cap 708 after they have been separated. Figure 4C is a perspective view depicting an exemplary embodiment of the distal end of applicator device 150 with electronics housing 706 and adhesive patch 105 removed from the positions they would have maintained within sensor carrier 710 of sheath 704 when cap 708 was in place.

[0064] 4D-4G, by way of example and not limitation, applicator device 20150 can be provided to a user as a single, integral assembly. FIGS. 4D and 4E provide perspective top and bottom views, respectively, of applicator device 20150, FIG. 4F provides an exploded view of applicator device 20150, and FIG. 4G provides a side cutaway view. These perspective views illustrate how applicator 20150 is shipped and received by a user. The exploded and cutaway views illustrate the components of applicator device 20150. The applicator device 20150 can include a housing 20702, a gasket 20701, a sheath 20704, a tip carrier 201102, a spring 205612, a sensor carrier 20710 (also referred to as a "puck carrier"), a tip hub 205014, a sensor control device (also referred to as a "puck") 20102, an adhesive patch 20105, a desiccant 20502, a cap 20708, a serial label 20709, and an tamper-evident feature 20712. When a user receives the shipment, only the housing 20702, the cap 20708, the tamper-evident feature 20712, and the label 20709 are visible. The tamper-evident feature 20712 may be, for example, a sticker coupled to each of the housing 20702 and the cap 20708, and may be, for example, irreparably damaged by separating the housing 20702 and the cap 20708, thereby indicating to the user that the housing 20702 and the cap 20708 may have been previously separated. These features are described in more detail below.

[0065] FIG. 5 shows an exemplary embodiment of a tray 810 having a removably coupled sterilization lid 812, and is a proximal perspective view that may represent how the package is shipped to a user and received by the user prior to assembly.

[0066] 6A is a close-up perspective cutaway view depicting the sensor delivery components within a tray 810. A platform 808 is slidably coupled within the tray 810. A desiccant 502 is fixed relative to the tray 810. A sensor module 504 is mounted within the tray 810.

[0067] 6B is a close-up perspective view depicting sensor module 504 in greater detail, where retention arm extension 1834 of platform 808 releasably secures sensor module 504 in place. Module 2200 is coupled with connector 2300, nib module 2500, and sensor (not shown), allowing them to be detached from one another as sensor module 504 during assembly.

[0068] 1 and 3A-3G , in a two-piece architecture system, the sensor tray 202 and the sensor applicator 102 are provided to the user in separate packages, thus requiring the user to unpack each package and ultimately assemble the system. In some applications, these separate sealed packages allow the sensor tray 202 and the sensor applicator 102 to be sterilized in separate sterilization processes that are specific to the contents of each package and incompatible with the contents of other packages. More specifically, the sensor tray 202, including the plug assembly 207, including the sensor 110 and the sharp 220, can be sterilized using radiation sterilization, such as electron beam (or “e-beam”) illumination. Suitable radiation sterilization processes include, but are not limited to, electron beam (e-beam) illumination, gamma ray illumination, x-ray illumination, or any combination thereof. However, radiation sterilization may damage electrical components positioned within the electronics housing of the sensor control device 102. As a result, if the sensor applicator 102, including the electronics housing of the sensor control device 102, needs to be sterilized, it can be sterilized by another method, such as gas chemical sterilization using, for example, ethylene oxide. However, gas chemical sterilization may destroy enzymes or other chemical and biological agents contained on the sensors 110. Due to this sterilization incompatibility, the sensor tray 202 and the sensor applicator 102 are typically sterilized in separate sterilization processes and then packaged separately, thereby requiring the user to ultimately assemble the components for use.

[0069] 7A and 7B are exploded top and bottom views, respectively, of a sensor control device 3702 in accordance with one or more embodiments. The shell 5006 and mount 5008 act as opposing clamshell halves that enclose or otherwise substantially encapsulate the various electronic components of the sensor control device 3702. As shown, the sensor control device 3702 may include a printed circuit board assembly (PCBA) 3802 that includes a printed circuit board (PCB) 3804 having a plurality of electronic modules 3806 coupled thereto. Exemplary electronic modules 3806 include, but are not limited to, resistors, transistors, capacitors, inductors, diodes, and switches. Conventional sensor control devices typically stack PCB components on only one side of the PCB. In contrast, the PCB components 3806 in the sensor control device 3702 may be distributed around the surface area of ​​both sides (i.e., the top and bottom) of the PCB 3804.

[0070] In addition to the electronics module 3806, the PCBA 3802 may further include a data processing unit 3808 mounted on the PCB 3804. The data processing unit 3808 may include, for example, an application specific integrated circuit (ASIC) configured to perform one or more functions or routines related to the operation of the sensor control device 3702. More specifically, the data processing unit 3808 may be configured to perform data processing functions, where such functions may include, but are not limited to, filtering and encoding multiple data signals each corresponding to a sampled analyte level of the user. The data processing unit 3808 may further include or otherwise communicate with an antenna for communicating with the reader device 106 (FIG. 1).

[0071] A battery opening 3810 is defined in the PCB 3804 and can be sized to receive and seat a battery 3812 configured to power the sensor control device 3702. An axial battery contact 3814a and a radial battery contact 3814b can be coupled to the PCB 3804 and can extend into the battery opening 3810 to facilitate the transfer of power from the battery 3812 to the PCB 3804. As the names suggest, the axial battery contact 3814a can be configured to provide axial contact to the battery 3812, while the radial battery contact 3814b can provide radial contact to the battery 3812. Positioning the battery 3812 in the battery opening 3810 with the battery contacts 3814a, 3814b helps reduce the height H of the sensor control device 3702, thereby allowing the PCB 3804 to be centered and its components to be distributed on both sides (i.e., top and bottom). This also helps facilitate providing corner surfaces 3718 on the electronics housing 3704 .

[0072] The sensor 3716 may be centrally positioned with respect to the PCB 3804 and may include a tail 3816, a flag 3818, and a neck 3820 interfacing the tail 3816 and the flag 3818. The tail 3816 may extend through a central opening 3720 in the mount 3708 and be configured to be transcutaneously received under the skin of a user. Additionally, the tail 3816 may have an enzyme or other chemical agent included thereon to assist in facilitating analyte monitoring.

[0073] The flag 3818 may include a generally flat surface having one or more sensor contacts 3822 (three shown in FIG. 7B ) positioned thereon. The sensor contacts 3822 may be configured to align with and engage one or more corresponding circuit contacts 3824 (three shown in FIG. 7A ) provided on the PCB 3804. In some embodiments, the sensor contacts 3822 may include a carbon-impregnated polymer printed or otherwise digitally applied to the flag 3818. Conventional sensor control devices typically include a connector fabricated from silicone rubber that encapsulates one or more flexible carbon-impregnated polymer modules that serve as conductive contacts between the sensor and the PCB. In contrast, the sensor contacts 3822 of the present disclosure provide a direct connection between the sensor 3716 and the PCB 3804, thereby eliminating the need for prior art connectors and advantageously reducing the height H. Furthermore, the elimination of the flexible carbon-impregnated polymer modules eliminates significant circuit resistance, thus improving circuit conductivity.

[0074] The sensor control device 3702 may further include a flexible member 3826 that may be positioned to be sandwiched between the flag 3818 and the inner surface of the shell 3706. More specifically, when the shell 3706 and the mount 3708 are assembled together, the flexible member 3826 may be configured to provide a passive biasing load against the flag 3818 that urges the sensor contacts 3822 into continuous engagement with the corresponding circuit contacts 3824. In the illustrated embodiment, the flexible member 3826 is a resilient O-ring, although it is contemplated that the flexible member 3826 may alternatively include any other type of biasing device or feature, such as a compression spring or the like, without departing from the scope of the present disclosure.

[0075] The sensor control device 3702 may further include one or more electromagnetic shields, shown as a first shield 3828a and a second shield. The shell 3706 may provide or otherwise define a first clocking receptacle 3830a (FIG. 7B) and a second clocking receptacle 3830b (FIG. 7B), and the mount 3708 may provide or otherwise define a first clocking post 3832a (FIG. 7A) and a second clocking post 3832b (FIG. 7A). The shell 3706 is properly aligned with the mount 3708 by mating the first and second clocking receptacles 3830a, 3830b with the first clocking posts 3832a, 3832b, respectively.

[0076] 7A , the inner surface of the mount 3708 can provide or otherwise define a plurality of pockets or recesses configured to receive various component parts of the sensor control device 3702 when the shell 3706 is mated to the mount 3708. For example, the inner surface of the mount 3708 can define a battery locator 3834 configured to receive a portion of the battery 3812 when the sensor control device 3702 is assembled. An adjacent contact pocket 3836 can be configured to receive a portion of the axial contact 3814a.

[0077] Additionally, a plurality of module pockets 3838 may be defined within the interior surface of the mount 3708 for receiving various electronic modules 3806 positioned on the bottom surface of the PCB 3804. Additionally, a shield locator 3840 may be defined within the interior surface of the mount 3708 for receiving at least a portion of the second shield 3828b when the sensor control device 3702 is assembled. The battery locator 3834, contact pocket 3836, module pocket 3838, and shield locator 3840 all extend a short distance into the interior surface of the mount 3708, such that the overall height H of the sensor control device 3702 may be reduced as compared to conventional sensor control devices. The module pocket 3838 may assist in minimizing the diameter of the PCB 3804 by allowing PCB components to be positioned on both sides (i.e., the top and bottom).

[0078] Continuing with reference to FIG. 7A , the mount 3708 can further include a plurality of carrier gripping features 3842 (two shown) defined about its periphery. The carrier gripping features 3842 are axially offset from a bottom surface 3844 of the mount 3708, where a transfer adhesive (not shown) can be applied during assembly. In contrast to conventional sensor control devices that typically include conical carrier gripping features that intersect the bottom surface of the mount, the carrier gripping features 3842 of the present disclosure are offset from this plane (i.e., bottom surface 3844), where the transfer adhesive is applied. This can prove advantageous by helping to ensure that the delivery system does not inadvertently attach to the transfer adhesive during assembly. Furthermore, the carrier gripping features 3842 of the present disclosure eliminate the need for a scalloped transfer adhesive, thereby facilitating the manufacture of the transfer adhesive and eliminating the need to precisely clock the transfer adhesive to the mount 3708. This, in turn, increases the bonding area and, therefore, the bond strength.

[0079] 7B , the bottom surface 3844 of the mount 3708 may provide or otherwise define a plurality of grooves 3846 that may be defined at or near the periphery of the mount 3708 and spaced equidistant from one another. A transfer adhesive (not shown) may be bonded to the bottom surface 3844, and the grooves 3846 may be configured to assist in transporting moisture from the sensor control device 3702 to around the mount 3708 during use. In some embodiments, the spacing of the grooves 3846 may be sandwiched between module pockets 3838 ( FIG. 7A ) defined on the opposite (inner) side of the mount 3708. As will be appreciated, alternating the locations of the grooves 3846 and the module pockets 3838 ensures that opposing features do not extend into one another on both sides of the mount 3708. This may help maximize material utilization for the mount 3708, thereby helping to maintain a minimum height H of the sensor control device 3702. The module pocket 3838 can significantly reduce mold collapse and improve the flatness of the bottom surface 3844 to which the transfer adhesive adheres.

[0080] 7B , the inner surface of the shell 3706 can also provide or otherwise define a plurality of pockets or recesses configured to receive various component parts of the sensor control device 3702 when the shell 3706 is mated to the mount 3708. For example, the inner surface of the shell 3706 can define a counter battery locator 3848 positionable opposite the battery locator 3834 ( FIG. 7A ) of the mount 3708 and configured to receive a portion of the battery 3812 when the sensor control device 3702 is assembled. The counter battery locator 3848 extends a short distance into the inner surface of the shell 3706, which helps to reduce the overall height H of the sensor control device 3702.

[0081] The inner surface of the shell 3706 may provide or otherwise define thereon a tip and sensor locator 3852. The tip and sensor locator 3852 may be configured to receive both a tip (not shown) and a portion of the sensor 3716. The tip and sensor locator 3852 may be configured to align and / or mate with a corresponding tip and sensor locator 2054 (FIG. 7A) provided on the inner surface of the mount 3708.

[0082] 8A-8C illustrate an alternative sensor assembly / electronics assembly connection technique in accordance with an embodiment of the present disclosure. As shown, the sensor assembly 14702 includes a sensor 14704, a connector support 14706, and a prong 14708. Among other things, a recess or receptacle 14710 can be defined in a bottom surface of a mount for the electronics assembly 14712, which can provide a location for receiving the sensor assembly 14702 and coupling it to the electronics assembly 14712, thereby fully assembling the sensor control device. The contours of the sensor assembly 14702 can be shaped in a manner that matches or is complementary to the receptacle 14710, which includes a resilient sealing member 14714 (including a conductive material that is coupled to a circuit board and aligns with the electrical contacts of the sensor 14704). 8C is formed when snapped or otherwise attached to the electronics assembly 14712 by pressing the sensor assembly 14702 into a recess 14710 integrally formed in the electronics assembly 14712. This embodiment provides an integral connector for the sensor assembly 14702 within the electronics assembly 14712.

[0083] Additional information regarding sensor assemblies is provided in U.S. Patent Publication Nos. 2013 / 0150691 and 2021 / 0204841, the entire contents of each of which are incorporated by reference herein.

[0084] In accordance with embodiments of the present disclosure, the sensor control device 102 can be modified to provide a one-piece architecture that can provide sterilization techniques specifically designed for the one-piece architecture sensor control device. The one-piece architecture allows the sensor applicator 150 and sensor control device 102 to be shipped to a user in a single sealed package that does not require any final user assembly steps. In other words, the user need only unpack one package and then deliver the sensor control device 102 to the target monitoring location. The one-piece system architecture described herein can prove advantageous by eliminating component parts, various fabrication process steps, and user assembly steps. This results in reduced packaging and waste, and mitigates user error or system contamination.

[0085] 9A and 9B are a side view and a cross-sectional side view, respectively, of an exemplary embodiment of the sensor applicator 102 coupled with the applicator cap 210. More specifically, FIG. 9A illustrates how the sensor applicator 102 may be shipped to and received by a user, and FIG. 9B depicts the sensor control device 4402 positioned within the sensor applicator 102. These figures show that the fully assembled sensor control device 4402 is already installed within the assembled sensor applicator 102 before delivery to the user, thus eliminating any additional steps that the user may otherwise have to perform.

[0086] The fully assembled sensor control device 4402 can be loaded into the sensor applicator 102, and then the applicator cap 210 can be coupled to the sensor applicator 102. In some embodiments, the applicator cap 210 can be threaded onto the housing 208 and can include an unsealing ring 4702. When the applicator cap 210 is rotated (e.g., twisted off) relative to the housing 208, the unsealing ring 4702 threads off, thereby allowing the applicator cap 210 to be released from the sensor applicator 102.

[0087] In accordance with the present disclosure, the sensor control device 4402, while loaded into the sensor applicator 102, can be subjected to gas chemical sterilization 4704 configured to sterilize its electronics housing 4404 and any other exposed parts. To effect this sterilization, chemicals can be injected into a sterilization chamber 4706 cooperatively defined by the sensor applicator 102 and the interfaced cap 210. In some applications, chemicals can be injected into the sterilization chamber 4706 through one or more vent ports 4708 defined in the applicator cap 210 at its proximal end 610. Exemplary chemicals that can be used for gas chemical sterilization 4704 include, but are not limited to, ethylene oxide, hydrogen peroxide vapor, nitrogen oxides (such as, for example, nitrous oxide, nitrogen dioxide), and steam.

[0088] The sensor 4410 and distal portion of the tip 4412 are sealed within the sensor cap 4416 so that the chemicals used during the gas chemical sterilization process do not interact with the enzymes, chemical agents, or biological agents disposed on the tail 4524 and other sensor components, such as the thin film coating that regulates analyte inflow.

[0089] Once the desired level of sterility has been reached within the sterilization chamber 4706, the gas solution can be removed and the sterilization chamber 4706 can be aerated. Aeration can be achieved by a series of vacuums followed by circulating a gas (e.g., nitrogen) or sterile air through the gas sterilization chamber 4706. Once the sterilization chamber 4706 is properly aerated, the vent port 4708 can be blocked with a seal 4712 (shown in dashed lines).

[0090] In some embodiments, the seal 4712 may include two or more layers composed of different materials. The first layer may be made of a synthetic material (e.g., flash-spun high-density polyethylene fiber) such as Tyvek® available from DuPont®. Tyvek® is durable, puncture-resistant, and allows vapor transmission. The Tyvek® layer may be applied prior to the gas-chemical sterilization process, and following the gas-chemical sterilization process, a foil or other steam- and moisture-resistant material layer may be sealed (e.g., heat-fused) over the Tyvek® layer to prevent the ingress of contaminants and moisture into the sterilization chamber 4706. In other embodiments, the seal 4712 may include only a single protective layer applied to the applicator cap 210. In such embodiments, this single layer may be gas-permeable for the sterilization process but may also provide protection against moisture and other harmful elements after the sterilization process is complete.

[0091] With the seal 4712 in place, the applicator cap 210 provides a barrier to external contamination, thereby maintaining a sterile environment for the assembled sensor control device 4402 until the user removes (unscrews) the applicator cap 210. The applicator cap 210 can create a dust-free environment that prevents the adhesive patch 4714 from becoming soiled during shipping and storage.

[0092] 10A and 10B are isometric and side views, respectively, of another exemplary sensor control device 5002 in accordance with one or more embodiments of the present disclosure. The sensor control device 5002 may be similar in some respects to the sensor control device 102 of FIG. 1 and, therefore, may be most clearly understood with reference thereto. Furthermore, the sensor control device 5002 may replace the sensor control device 102 of FIG. 1 and, therefore, may be used in conjunction with the sensor applicator 102 of FIG. 1, which may deliver the sensor control device 5002 to a target monitoring location on a user's skin.

[0093] 1, however, the sensor control device 5002 may include a one-piece system architecture that does not require a user to unpack multiple packages and perform final assembly of the sensor control device 5002 prior to application. In other words, upon receipt by the user, the sensor control device 5002 is already fully assembled and properly positioned within the sensor applicator 150 (FIG. 1). To use the sensor control device 5002, the user need only open a single barrier (e.g., applicator cap 708 of FIG. 3B) for use, after which the sensor control device 5002 is immediately delivered to the target monitoring location.

[0094] As shown, the sensor control device 5002 includes an electronics housing 5004 that is generally disc-shaped and may have a circular cross-section. However, in other embodiments, the electronics housing 5004 may exhibit other cross-sectional shapes, such as oval or polygonal, without departing from the scope of this disclosure. The electronics housing 5004 may be configured to house or otherwise contain various electrical components used to operate the sensor control device 5002. In at least one embodiment, an adhesive patch (not shown) may be positioned on the bottom surface of the electronics housing 5004. The adhesive patch may be similar to adhesive patch 105 of FIG. 1 and, therefore, may assist in adhering the sensor control device 5002 to a user's skin for use.

[0095] As shown, the sensor control device 5002 includes an electronics housing 5004 that includes a shell 5006 and a mateable mount 5008. The shell 5006 may be secured to the mount 5008 by a variety of methods, such as a snap engagement, an interference fit, sonic welding, one or more mechanical fasteners (e.g., screws), a gasket, an adhesive, or any combination thereof. In some cases, the shell 5006 may be secured to the mount 5008 such that a sealed interface is created between the shell 5006 and the mount 5008.

[0096] The sensor control device 5002 may further include a sensor 5010 (partially visible) and a tip 5012 (partially visible) used to assist in transcutaneously delivering the sensor 5010 beneath the user's skin during application of the sensor control device 5002. As shown, corresponding portions of the sensor 5010 and tip 5012 extend distally from a bottom surface of the electronics housing 5004 (e.g., mount 5008). The tip 5012 may include a tip hub 5014 configured to securely support the tip 5012. As seen most clearly in FIG. 10B , the tip hub 5014 may include or otherwise define a mating member 5016. To couple the tip 5012 to the sensor control device 5002, the tip 5012 can be advanced axially through the electronics housing 5004 until the tip hub 5014 engages the top surface of the shell 5006 and the mating member 5016 extends distally from the bottom surface of the mount 5008. Once the tip 5012 penetrates the electronics housing 5004, the exposed portion of the sensor 5010 can be received within the hollow or recessed (arcuate) portion of the tip 5012. The remainder of the sensor 5010 is positioned within the electronics housing 5004.

[0097] The sensor control device 5002 may further include a sensor cap 5018, which is shown disassembled or detached from the electronics housing 5004 in FIGS. 10A-10B. The sensor cap 5018 may be removably coupled to the sensor control device 5002 (e.g., the electronics housing 5004) at or near the bottom of the mount 5008. The sensor cap 5018 may assist in providing a hermetic barrier surrounding the exposed portions of the sensor 5010 and the sharp 5012 to protect them from gaseous chemical sterilization. As shown, the sensor cap 5018 may include a generally cylindrical body having a first end 5020a and an opposing second end 5020b. The first end 5020a may be open to provide access to an interior chamber 5022 defined within the body. In contrast, the second end 5020b may be closed and may provide or otherwise define an engagement feature 5024. As described herein, the engagement feature 5024 can assist in mating the sensor cap 5018 to a cap (e.g., applicator cap 708 of FIG. 3B) of a sensor applicator (e.g., sensor applicator 150 of FIGS. 1 and 3A-3G) and can assist in removing the sensor cap 5018 from the sensor control device 5002 when the cap is removed from the sensor applicator.

[0098] The sensor cap 5018 can be removably coupled to the electronics housing 5004 at or near a bottom surface of the mount 5008. More specifically, the sensor cap 5018 can be removably coupled to a mating member 5016 that extends distally from the bottom surface of the mount 5008. In at least one embodiment, for example, the mating member 5016 can define a set of external threads 5026a ( FIG. 10B ) that can mate with a set of internal threads 5026b ( FIG. 10A ) defined by the sensor cap 5018. In some embodiments, the external and internal threads 5026a, 5026b can include a square thread design (e.g., lacking a helical curvature), which can prove advantageous for molding these parts. Alternatively, the external and internal threads 5026a, 5026b can include a helical thread engagement. Thus, the sensor cap 5018 can be threadably coupled to the sensor control device 5002 at the mating member 5016 of the point hub 5014. In other embodiments, the sensor cap 5018 can be removably coupled to the mating member 5016 by other types of engagement, including, but not limited to, an interference fit or a friction fit, or a frangible member or material that can be broken with a small separation force (e.g., axial or rotational force).

[0099] In some embodiments, the sensor cap 5018 may include a unitary (single) structure extending between the first end 5020a and the second end 5020b. However, in other embodiments, the sensor cap 5018 may include two or more component parts. In the illustrated embodiment, for example, the sensor cap 5018 may include a sealing ring 5028 positioned at the first end 5020a and a desiccant cap 5030 positioned at the second end 5020b. The sealing ring 5028 may assist in sealing the inner chamber 5022, as described in more detail below. In at least one embodiment, the sealing ring 5028 may include an elastomeric O-ring. The desiccant cap 5030 may store or include a desiccant that assists in maintaining a preferred humidity level within the inner chamber 5022. Additionally, the desiccant cap 5030 may define or otherwise provide an engagement feature 5024 for the sensor cap 5018.

[0100] 11A-11C are staged cross-sectional side views illustrating the assembly of a sensor applicator 102 and a sensor control device 5002 according to one or more embodiments. Once the sensor control device 5002 is fully assembled, it can be loaded into the sensor applicator 102. Referring to FIG. 11A, the sharp body hub 5014 can include or otherwise define hub snap tabs 5302 configured to assist in coupling the sensor control device 5002 to the sensor applicator 102. More specifically, the sensor control device 5002 can be advanced into the sensor applicator 102, and the hub snap tabs 5302 can be received by corresponding arms 5304 of a sharp body carrier 5306 positioned within the sensor applicator 102.

[0101] 11B shows the sensor control device 5002 received by the sharp body carrier 5306 and thus secured within the sensor applicator 102. Once the sensor control device 5002 is loaded into the sensor applicator 102, the applicator cap 210 can be coupled to the sensor applicator 102. In some embodiments, the applicator cap 210 and the housing 208 can have a set of intermateable threads 5308 that allow the applicator cap 210 to be twisted onto the housing 208 in a clockwise (or counterclockwise) direction, thereby securing the applicator cap 210 to the sensor applicator 102.

[0102] As shown, a sheath 212 is further positioned within the sensor applicator 102, and the sensor applicator 102 can include a sheath locking mechanism 5310 configured to ensure that the sheath 212 does not prematurely collapse during an impact event. In the illustrated embodiment, the sheath locking mechanism 5310 can include a threaded engagement between the applicator cap 210 and the sheath 212. More specifically, one or more internal threads 5312a can be defined or otherwise provided on an inner surface of the applicator cap 210, and one or more external threads 5312b can be defined or otherwise provided on the sheath 212. The internal threads 5312a and external threads 5312b can be configured to threadably mate when the applicator cap 210 is threaded onto the sensor applicator 102 at the threads 5308. The female and male threads 5312 a , 5312 b can have the same thread pitch as the threads 5308 that allow the applicator cap 210 to be twisted onto the housing 208 .

[0103] 11C shows applicator cap 210 fully threaded (coupled) to housing 208. As shown, applicator cap 210 may further include or otherwise define a cap post 5314 centrally positioned therein and extending proximally from a bottom surface of applicator cap 210. Cap post 5314 may be configured to receive at least a portion of sensor cap 5018 when applicator cap 210 is twisted onto housing 208.

[0104] With the sensor control device 5002 loaded into the sensor applicator 102 and the applicator cap 210 properly secured, the sensor control device 5002 can then be subjected to a gas chemical sterilization configured to sterilize the electronics housing 5004 and any other exposed portions of the sensor control device 5002. Because the sensor 5010 and the distal portion of the sharp 5012 are sealed within the sensor cap 5018, the chemicals used during the gas chemical sterilization process cannot interact with the enzymes, chemical agents, and biological agents disposed on the tail 5104 and other sensor components, such as the thin film coating that conditions the analyte inflow.

[0105] 12A-12C are step-by-step cross-sectional side views illustrating assembly and disassembly of an alternative embodiment of a sensor applicator 102 and a sensor control device 5002 according to one or more additional embodiments. As generally described above, the fully assembled sensor control device 5002 can be loaded into the sensor applicator 150 by coupling the hub snap claws 5302 into the arms 5304 of a sharp body carrier 5306 positioned within the sensor applicator 150.

[0106] In the illustrated embodiment, the sheath arm 5604 of the sheath 212 can be configured to interact with a first detent 5702a and a second detent 5702b defined within the housing 208. The first detent 5702a may alternatively be referred to as a “locking” detent, and the second detent 5702b may alternatively be referred to as a “firing” detent. When the sensor control device 5002 is initially installed within the sensor applicator 150, the sheath arm 5604 can be received within the first detent 5702a. As described below, the sheath 212 can be actuated to move the sheath arm 5604 to the second detent 5702b, thereby placing the sensor applicator 150 in a fired position.

[0107] 12B , applicator cap 210 is aligned with and advanced toward housing 208 so that sheath 212 is received within applicator cap 210. To couple applicator cap 210 to housing 208, instead of rotating applicator cap 210 relative to housing 208, the threads of applicator cap 210 can snap onto corresponding threads of housing 208. Axial cuts or slots 5703 (one shown) defined in applicator cap 210 can allow a portion of applicator cap 210 proximal to its threads to bend outward and snap into engagement with the threads of housing 208. When applicator cap 210 is snapped onto housing 208, sensor cap 5018 can be snapped into cap post 5314 accordingly.

[0108] 11A-11C , the sensor applicator 102 can include a sheath locking mechanism configured to ensure that the sheath 212 does not prematurely collapse during an impact event. In the illustrated embodiment, the sheath locking mechanism includes one or more ribs 5704 (one shown) defined near the base of the sheath 212 and configured to interact with one or more ribs 5706 (two shown) and a shoulder 5708 defined near the base of the applicator cap 210. The rib 5704 can be configured to engage between the rib 5706 and the shoulder 5708 during attachment of the applicator cap 210 to the housing 208. More specifically, once applicator cap 210 is snapped onto housing 208, applicator cap 210 can be rotated (e.g., clockwise) such that rib 5704 of sheath 212 is positioned between rib 5706 and shoulder 5708 of applicator cap 210, which “locks” applicator cap 210 in place until a user counter-rotates applicator cap 210 to remove it for use. The engagement of rib 5704 between rib 5706 and shoulder 5708 of applicator cap 210 can prevent sheath 212 from prematurely collapsing.

[0109] 12C, the applicator cap 210 has been removed from the housing 208. As with the embodiment of FIGS. 21A-21C, the applicator cap 210 can be removed by counter-rotating it, which correspondingly rotates the cap post 5314 in the same direction, unscrewing the sensor cap 5018 from the fitting 5016, substantially as described above. Further, disconnecting the sensor cap 5018 from the sensor control device 5002 exposes the sensor 5010 and a distal portion of the tip 5012.

[0110] When applicator cap 210 is unscrewed from housing 208, rib 5704 defined on sheath 212 can slidingly engage an upper surface of rib 5706 defined on applicator cap 210. The upper surface of rib 5706 can provide a corresponding raised surface that causes upward displacement of sheath 212 when applicator cap 210 is rotated, moving sheath 212 upward and bending sheath arm 5604 out of engagement with first detent 5702a and into second detent 5702b. When sheath 212 moves to second detent 5702b, radial shoulder 5614 disengages from radial engagement with carrier arm 5608, thereby causing the passive spring force of spring 5612 to push tip carrier 5306 upward, forcing carrier arm 5608 out of engagement with groove 5610. As the sharps carrier 5306 moves upward within the housing 208, the engaging member 5016 may correspondingly retract until it is flush, substantially flush, or near-flush with the bottom surface of the sensor control device 5002. At this point, the sensor applicator 102 is in the fired position. Thus, in this embodiment, removing the applicator cap 210 correspondingly retracts the engaging member 5016.

[0111] 13A-13F illustrate exemplary details of an embodiment of the internal device configuration for "firing" the applicator 216 to apply the sensor control device 222 to a user, including safely retracting the sharp 1030 back into the used applicator 216. Together, these figures depict an exemplary sequence of driving the sharp 1030 (carrying a sensor coupled to the sensor control device 222) into the user's skin, withdrawing the sharp while leaving the sensor in operable contact with the user's interstitial fluid, and adhesively adhering the sensor control device to the user's skin. With reference to these figures, one skilled in the art will be able to discern modifications of such operations for use with alternative applicator assembly embodiments and components. Additionally, the applicator 216 can be a sensor applicator having a one-piece or two-piece architecture as disclosed herein.

[0112] 13A , the sensor 1102 is supported within the tip 1030 slightly above the user's skin 1104. Rails 1106 (optionally three rails 1106) on the upper guide section 1108 can be provided to control movement of the applicator 216 relative to the sheath 318. The sheath 318 is secured within the applicator 216 by a detent feature 1110 such that an appropriate downward force along the longitudinal axis of the applicator 216 will overcome the resistance provided by the detent feature 1110 so that the tip 1030 and sensor control device 222 can translate along the longitudinal axis into (and onto) the user's skin 1104. Additionally, the catch arm 1112 of the sensor carrier 1022 engages the tip retraction assembly 1024 to maintain the tip 1030 in position relative to the sensor control device 222.

[0113] 13B, a user force is applied to overcome and disable the detent feature 1110, causing the sheath 318 to collapse into the housing 314 and drive the sensor control device 222 (together with the attached portions) to translate downward along the longitudinal axis as shown by arrow L. The inner diameter of the upper guide section 1108 of the sheath 318 constrains the position of the carrier arm 1112 throughout the entire stroke of the sensor / sharp insertion process. The retention of the stop surface 1114 of the carrier arm 1112 against the complementary surface 1116 of the sharp retraction assembly 1024 maintains the position of these members with the return spring 1118 fully biased. According to an embodiment, instead of using user force to drive the sensor control device 222 to translate downward along the longitudinal axis as shown by arrow L, the housing 314 can include a button (by way of example and not limitation, a push button) that activates a drive spring (by way of example and not limitation, a coil spring) to drive the sensor control device 222.

[0114] In Figure 13C, the sensor 1102 and tip 1030 have reached maximum insertion depth. In doing so, the carrier arm 1112 passes through the inner diameter of the upper guide section 1108. The compressive force of the coil return spring 1118 then drives the angled stop surface 1114 radially outward, releasing a force that drives the tip carrier 1102 of the tip retraction assembly 1024 to pull the (slotted or otherwise configured) tip 1030 out of the user and away from the sensor 1102, as shown by arrow R in Figure 13D.

[0115] With the sharp 1030 fully retracted, as shown in Figure 13E, the final locking mechanism 1120 is engaged with the upper guide section 1108 of the sheath 318. As shown in Figure 13F, the used applicator assembly 216 is removed from the insertion site, leaving the sensor control device 222 behind and with the sharp 1030 safely secured inside the applicator assembly 216. At this point, the used applicator assembly 216 is ready to be discarded.

[0116] Actuation of the applicator 216 when attaching the sensor control device 222 is designed to give the user the sensation that both insertion and retraction of the point 1030 are performed automatically by the internal functions of the applicator 216. In other words, the present invention avoids the user from feeling as if they are forcing the point 1030 into their skin. Thus, after the user applies enough force to overcome the resistance from the detent function of the applicator 216, the resulting action of the applicator 216 is perceived as an automatic response to the applicator being "triggered." Even though all of the driving force for inserting the point 1030 is provided by the user and no additional biasing / driving means is used, the user does not perceive that they are supplying additional force to drive the point 1030 to penetrate the skin. As detailed above in FIG. 13C , retraction of the point 1030 is automated by the coil return spring 1118 of the applicator 216.

[0117] Those skilled in the art will appreciate that with respect to any of the applicator embodiments described herein, and any of the components of the applicator embodiments, including but not limited to, tip embodiments, tip module embodiments, and sensor module embodiments, these embodiments can be sized and configured to be suitable for use with a sensor configured to sense an analyte level in a bodily fluid within the epidermis, dermis, or subcutaneous tissue of a subject. In some embodiments, for example, the tip and distal portion of the analyte sensor disclosed herein can be sized and configured to be positioned at a particular distal depth (i.e., the deepest penetration point into a tissue or layer of a subject's body, e.g., the epidermis, dermis, or subcutaneous tissue). Those skilled in the art will appreciate that with respect to some applicator embodiments, certain embodiments of the tip can be sized and configured to be positioned at a different distal depth within the subject's body compared to the final distal depth of the analyte sensor. In some embodiments, for example, the tip can be positioned at a first distal depth within the subject's epidermis prior to retraction, while the distal portion of the analyte sensor can be positioned at a second distal depth within the subject's dermis. In other embodiments, the tip may be positioned at a first distal depth within the dermis of the subject prior to retraction, while the distal portion of the analyte sensor may be positioned at a second distal depth within the subcutaneous tissue of the subject. In yet other embodiments, the tip may be positioned at a first distal depth and the analyte sensor may be positioned at a second distal depth prior to retraction, both within the same layer or tissue of the subject's body.

[0118] Additionally, those skilled in the art will appreciate that for any of the applicators described herein, the analyte sensor and one or more structured components coupled to the analyte sensor, including but not limited to one or more spring mechanisms, can be positioned in an off-center position within the applicator relative to one or more axes thereof. In some applicator embodiments, for example, the analyte sensor and spring mechanism can be positioned in a first off-center position on a first side of the applicator relative to the applicator axis, and the sensor electronics can be positioned in a second off-center position on a second side of the applicator relative to the applicator axis. In other applicator embodiments, the analyte sensor, spring mechanism, and sensor electronics can be positioned in off-center positions on the same side of the applicator axis. Those skilled in the art will appreciate that other permutations and configurations in which any or all of the analyte sensor, spring mechanism, sensor electronics, and other applicator components are positioned in central or off-center positions relative to one or more axes of the applicator are possible and fully within the scope of the present disclosure.

[0119] Additional details of suitable devices, systems, methods, components, and their operation, along with associated features, are described in International Patent Publication No. WO 2018 / 136898 to Rao et al., International Patent Publication No. WO 2019 / 236850 to Thomas et al., International Patent Publication No. WO 2019 / 236859 to Thomas et al., International Patent Publication No. WO 2019 / 236876 to Thomas et al., and U.S. Patent Publication No. 2020 / 0196919, filed June 6, 2019, the entire contents of each of which are incorporated herein by reference. Additional details regarding the applicator, embodiments of its components, and variations thereof are described in U.S. Patent Publication Nos. 2013 / 0150691, 2016 / 0331283, and 2018 / 0235520, the entire contents of all of which are incorporated herein by reference for all purposes. Additional details regarding the tip module, tips, embodiments of its components, and variations thereof are described in U.S. Patent Publication No. 2014 / 0171771, the entire contents of which are incorporated herein by reference for all purposes.

[0120] Biochemical sensors can be described by one or more sensing properties. A common sensing property is called the sensitivity of a biochemical sensor, which is a measure of the sensor's responsiveness to the concentration or composition of the chemical it is designed to detect. In electrochemical sensors, this response may be in the form of current (amperometric) or charge (coulometric). In other types of sensors, the response may be in a different form, such as photon intensity (e.g., light). The sensitivity of a biochemical analyte sensor can vary depending on several factors, including whether the sensor is in an in vitro or in vivo state.

[0121] FIG. 14 is a graph depicting the in vitro sensitivity of an amperometric analyte sensor. In vitro sensitivity can be obtained by testing the sensor in vitro at various analyte concentrations and then performing a regression (e.g., linear or nonlinear) or other curve fit on the resulting data. In this example, the sensitivity of the analyte sensor is linear or substantially linear and can be modeled according to the equation y=mx+b, where y is the sensor's output current, x is the analyte level (or concentration), m is the sensitivity slope, and b is the sensitivity intercept, which corresponds approximately to the background signal (e.g., noise). For sensors with a linear or substantially linear response, the analyte level corresponding to a given current can be determined from the sensitivity slope and intercept. Sensors with nonlinear sensitivity require additional information to determine the analyte level resulting from the sensor's output current, and those skilled in the art will be familiar with schemes for modeling nonlinear sensitivity. In certain embodiments of in vivo sensors, the in vitro sensitivity may be the same as the in vivo sensitivity, while in other embodiments, a transfer (or transformation) function is used to convert the in vitro sensitivity to an in vivo sensitivity applicable to the sensor's intended in vivo use.

[0122] Calibration is a technique for improving or maintaining accuracy by adjusting the measured output of a sensor to reduce the difference from the expected output of the sensor. One or more parameters describing the sensing characteristics of the sensor, such as sensitivity, are established for use in making the calibration adjustments.

[0123] Certain in-vivo analyte monitor systems require calibration, either by user intervention after implantation of the sensor in a user or patient, or automatically by the system itself. For example, when user intervention is required, the user performs an in-vitro measurement (e.g., a blood glucose (BG) measurement using a fingerstick and an in-vitro test strip) while the analyte sensor is implanted and enters the measurement into the system. The system compares the in-vitro measurement to the in-vivo signal and uses the difference to determine an estimate of the sensor's in-vivo sensitivity. The in-vivo sensitivity can then be used in an algorithmic process to convert data collected with the sensor into a value indicative of the user's analyte level. This process, and others that require user action to perform calibration, are referred to as "user calibration." Systems may require user calibration due to instability in sensor sensitivity, such as sensitivity drifting or changing over time. Thus, multiple user calibrations (e.g., on a periodic (e.g., daily) schedule, according to a variable schedule, or as needed) may be required to maintain accuracy. Although the embodiments described herein may incorporate some degree of user calibration as appropriate for a particular implementation, user calibration is generally not preferred as it requires the user to perform painful or otherwise difficult BG measurements and can introduce user error.

[0124] Some in vivo analyte monitor systems can periodically adjust calibration parameters through the use of automated measurements of sensor characteristics performed by the system itself (e.g., processing circuitry running software). Repeated adjustment of sensor sensitivity based on variables measured by the system (rather than the user) is commonly referred to as "system" (or automatic) calibration, and can be performed with or without user calibration, such as the BG measurements described above. As with repeated user calibration, repeated system calibration is typically necessitated by drift in sensor sensitivity over time. Thus, while the embodiments described herein can be used with some degree of automated system calibration, preferably the sensor sensitivity is relatively stable over time such that calibration is not required after each run.

[0125] Some in vivo analyte monitor systems operate with factory-calibrated sensors. Factory calibration refers to the determination or estimation of one or more calibration parameters prior to delivery to a user or healthcare professional (HCP). The calibration parameters may be determined by the sensor manufacturer (or by the manufacturer of other components of the sensor-control device, if different from the sensor manufacturer). Many in vivo sensor manufacturing processes process sensors in groups or batches, also called production lots, manufacturing lots, or simply lots. A single lot may contain thousands of sensors.

[0126] The sensor may include a calibration code or calibration parameters that may be derived or determined during one or more sensor manufacturing processes and encoded or programmed into a data processing device of the analyte monitoring system as part of the manufacturing process, or may be provided on the sensor itself, for example, as a bar code, laser tag, RFID tag, or other machine-readable information displayed on the sensor. When the code is provided to a receiver (or other data processing device), user calibration during in-vivo use of the sensor may be avoided or the frequency of in-vivo calibration while the sensor is being worn may be reduced. In embodiments in which the calibration code or calibration parameters are provided on the sensor itself, the calibration code or calibration parameters may be automatically transmitted or provided to a data processing device in the analyte monitoring system prior to or at the start of sensor use.

[0127] Some in vivo analyte monitor systems operate with sensors that can be one or more of factory-calibrated, system-calibrated, and / or user-calibrated. For example, a sensor can be provided with a calibration code or calibration parameters that can enable factory calibration. If this information is provided to the receiver (e.g., entered by a user), the sensor can operate as a factory-calibrated sensor. If this information is not provided to the receiver, the sensor can operate as a user-calibrated sensor and / or a system-calibrated sensor.

[0128] In yet another aspect, programming or executable instructions can be provided or stored within the data processing device and / or receiver / controller unit of the analyte monitoring system for providing a time-varying adjustment algorithm to the in-vivo sensor during use. For example, a predetermined curve or analysis curve or database can be generated based on retrospective statistical analysis of the in-vivo analyte sensor and corresponding glucose level feedback, which is time-based and configured to apply additional adjustments to one or more in-vivo sensor parameters to compensate for potential sensor drift or other factors in the stability profile.

[0129] In accordance with the presently disclosed subject matter, an analyte monitoring system can be configured to compensate or adjust sensor sensitivity based on a sensor drift profile. A time-varying parameter β(t) can be defined or determined based on an analysis of sensor behavior during in vivo use, and a time-varying drift profile can be determined. In certain aspects, the compensation or adjustment of sensor sensitivity can be programmed into a receiver unit, controller, or data processor of the analyte monitoring system such that the compensation or adjustment, or both, can be performed automatically and / or iteratively as sensor data is received from the analyte sensor. In accordance with the presently disclosed subject matter, the adjustment or compensation algorithm can be user-initiated or executed (rather than self-initiated or self-executing) such that the adjustment or compensation of the analyte sensor sensitivity profile is performed or executed upon user initiation or invocation of a corresponding function or routine or when the user enters a sensor calibration code.

[0130] In accordance with the presently disclosed subject matter, each sensor in a sensor lot (which may not include a sample sensor used for in vivo testing) can be non-destructively inspected to determine or measure sensor characteristics, such as film thickness at one or more points on the sensor, and other characteristics, including physical characteristics such as the area / volume of the active area. Such measurements or determinations can be performed in an automated manner, for example, using an optical scanner or other suitable measurement device or system, and the determined sensor characteristics for each sensor in the sensor lot are compared to corresponding average values ​​based on the sample sensors for possible correction of calibration parameters or calibration codes assigned to each sensor. For example, for a calibration parameter defined as sensor sensitivity, sensitivity is approximately inversely proportional to film thickness; thus, for example, for a sensor having a measured film thickness that is approximately 4% greater than the average film thickness for sensors sampled from the same sensor lot, in one embodiment the sensitivity assigned to the sensor is the average sensitivity determined from the sample sensors divided by 1.04. Similarly, sensitivity is approximately proportional to the active area of ​​the sensor, so that for a sensor with a measured active area that is approximately 3% smaller than the average active area for sensors sampled from the same sensor lot, the sensitivity assigned to that sensor is the average sensitivity multiplied by 0.97. The assigned sensitivity can be determined from the average sensitivity from the sample sensors by multiple successive adjustments for each test or measurement of that sensor. In certain embodiments, the test or measurement of each sensor can further include measuring the film thickness and / or the area or volume of the active sensing area as well as the viscosity or texture of the film.

[0131] Additional information regarding sensor calibration is provided in U.S. Patent Publication Nos. 2010 / 00230285 and 2019 / 0274598, the entire contents of each of which are incorporated herein by reference.

[0132] The storage memory 5030 of the sensor 110 may include software blocks related to the communication protocol of the communication module. For example, the storage memory 5030 may include a BLE service software block whose function is to provide an interface that makes the BLE module 5041 available to the computer hardware of the sensor 110. These software functions may include a BLE logic interface and an interface parser. BLE services provided by the communication module 5040 may include a generic access profile service, a generic attribute service, a generic access service, a device information service, a data transmission service, and a security service. The data transmission service may be a primary service used to transmit data such as sensor control data, sensor status data, analyte measurement data (past and present), and event log data. Sensor status data may include error data, currently active, and software state. Analyte measurement data may include information such as current and past raw measurements, current and past values ​​after processing with appropriate algorithms or models, predictions and trends of measurement levels, comparisons of other values ​​to patient-specific averages, invocation of actions determined by algorithms or models, and other similar types of data.

[0133] According to aspects of the presently disclosed subject matter, as embodied herein, the sensor 110 can be configured to communicate with multiple devices simultaneously by adapting the capabilities of its hardware and radio to the communication protocol or medium supported by the sensor 110. As an example, the BLE module 5041 of the communication module 5040 can be provided with software or firmware to enable multiple simultaneous connections between the sensor 110 as a central device and multiple other devices as peripheral devices, or multiple simultaneous connections of the sensor 110 as a peripheral device when another device is the central device.

[0134] A connection between two devices using a communication protocol such as BLE, and the resulting communication session, can be characterized by a similar physical channel operating between the two devices (e.g., the sensor 110 and the data receiving device 120). The physical channel can include a single channel or a set of channels, including, by way of example and not limitation, using an agreed-upon set of channels determined by a common clock and a channel hopping or frequency hopping sequence. A communication session can use a similar amount of available communication spectrum, and multiple such communication sessions can exist in the vicinity. In certain embodiments, each set of devices in a communication session uses a different physical channel or set of physical channels to manage interference with the same nearby devices.

[0135] For purposes of illustration and not limitation, reference will be made to an exemplary embodiment of a procedure for sensor-receiver connection for use with the subject matter of this disclosure. First, the sensor 110 repeatedly advertises its connection information to its environment in search of the data receiving device 120. The sensor 110 can repeat the advertisement periodically until a connection is established. The data receiving device 120 detects the advertisement packet and scans and filters for the sensor 120 to connect using the data provided therein. Next, the data receiving device 120 sends a scan request command, and the sensor 110 responds with a scan response packet providing additional details. Next, the data receiving device 120 sends a connection request using the associated Bluetooth device address. The data receiving device 120 can continue to request to establish a connection to the sensor 110 using the specific Bluetooth device address. Next, the devices establish an initial connection that allows them to begin exchanging data with each other. The devices begin the process of initializing data exchange services and performing mutual authentication procedures.

[0136] During the initial connection between the sensor 110 and the data receiving device 120, the data receiving device 120 can initialize a service, feature, and attribute discovery procedure. The data receiving device 120 can evaluate these capabilities of the sensor 110 and store them for use during subsequent connections. The sensor 110 and the data receiving device 120 then enable notification of the respective corresponding security services to be used for mutual authentication of these devices. The mutual authentication procedure can be automated and may not require user intervention. Following successful completion of the mutual authentication procedure, the sensor 110 sends a connection parameter update to request that the data receiving device 120 use connection parameter settings configured for itself, preferably to maximize longevity.

[0137] The data receiving device 120 then implements a sensor control procedure to backfill the historical data, current data, event log, and factory data. As an example, the data receiving device 120 sends a request to initiate the backfill process for each type of data. The request can specify a defined recording range, for example, based on measurements or timestamps, as needed. The sensor 110 responds with the requested data until all previously unsent data in its memory has been sent to the data receiving device 120. The sensor 110 can respond to the backfill request from the data receiving device 120 by indicating that all data has been sent. Once backfilling is complete, the data receiving device 120 can notify the sensor 110 that it is ready to receive periodic measurement readings. The sensor 110 can repeatedly send the readings over multiple notifications. As embodied herein, the multiple notifications can be redundant notifications to ensure that the data is transmitted correctly. Alternatively, the multiple notifications can comprise a single payload.

[0138] For purposes of illustration and not limitation, reference will be made to an exemplary embodiment of a procedure for sending a shutdown command to the sensor 110. The shutdown operation is performed when the sensor 110 is in, for example, an error state, a misinsertion state, or an expired sensor state. If the sensor 110 is not in these states, the sensor 110 can record the command and execute the shutdown when the sensor 110 transitions to the error state or the expired sensor state. The data receiving device 120 sends a properly formatted shutdown command to the sensor 110. If the sensor 110 is in an active state and processing another command, it will respond with a standard error response indicating that the sensor 110 is busy. Otherwise, the sensor 110 will send a response upon receiving the command. Additionally, the sensor 110 sends a success notification via sensor control, which may include sending an acknowledgment that the command was received. The sensor 110 registers the shutdown command. At the next appropriate opportunity (e.g., depending on the current sensor state as described herein), the sensor 110 will shut down.

[0139] For purposes of illustration and not limitation, reference is made to an exemplary embodiment of a high-level depiction of a state machine representation 6000 of actions that may be taken by the sensor 110, as shown in FIG. 15 . After initialization, the sensor 110 enters a state 6005 related to its manufacture. In the manufacture state 6005, the sensor 110 may be configured for operation, e.g., writing to the storage memory 5030. At various times while in state 6005, the sensor 110 checks for a received command to move to the save state 6015. Upon entering the save state 6015, the sensor performs a software integrity check. While in the save state 6015, the sensor may receive a wake-up request command, after which it progresses to the insertion detect state 6025.

[0140] Upon entering state 6025, the sensor 110 may store information about devices authorized to communicate with the sensor, as configured during startup, or initialize algorithms related to processing and interpreting measurements from the sensing hardware 5060. The sensor 110 may start a lifecycle timer responsible for maintaining its active operation time count, begin communicating with authorized devices, and transmit recorded data. While in insertion detection state 6025, the sensor 110 may enter state 6030, where it checks whether the operation time is equal to a predetermined threshold. This operation time threshold may correspond to a timeout function for determining whether insertion is successful. If the operation time threshold is reached, the sensor 110 proceeds to state 6035, where it checks whether the average data read volume is greater than a threshold volume, which corresponds to the expected data read volume for triggering detection of a successful insertion. If the data read volume is lower than the threshold volume while in state 6035, the sensor proceeds to state 6040, corresponding to a failed insertion. If the amount of data read meets the threshold, the sensor proceeds to the active pairing state 6055.

[0141] The active pairing state 6055 of the sensor 110 reflects a state in which the sensor 110 is operating normally by recording measurements, processing measurements, and reporting these measurements as needed. While in the active pairing state 6055, the sensor 110 sends measurements or attempts to establish a connection with the receiving device 120. The sensor 110 further increments its operating time. The sensor 110 transitions to the active lapsed state 6065 once it reaches a predetermined threshold operating time (e.g., when the operating time reaches a predetermined threshold). The active lapsed state 6065 of the sensor 110 reflects a state in which the sensor 110 has operated for its maximum predetermined amount of time.

[0142] While in the active-relapsed state 6065, the sensor 110 may generally perform operations related to gradually winding down operation and ensuring, if necessary, that collected measurements have been securely transmitted to the receiving device. For example, while in the active-relapsed state 6065, the sensor 110 may transmit collected data and, if a connection is unavailable, may intensify attempts to find and establish a connection with nearby authenticated devices. While in the active-relapsed state 6065, the sensor 110 may receive a shutdown command in state 6070. If a shutdown command is not received, the sensor 110 may check whether the operation time has exceeded a final operation threshold in state 6075. The final operation threshold may be based on the battery life of the sensor 110. The normal transmission state 6080 corresponds to a final operation of the sensor 110 and ultimately shuts down the sensor 110.

[0143] Before the sensor is powered up, the ASIC 5000 is in a low-power storage mode. The power-up process can begin, for example, when an incident RF field (e.g., an NFC field) drives the voltage of the power supply to the ASIC 5000 above a reset threshold, causing the sensor 110 to enter a wake-up state. While in the wake-up state, the ASIC 5000 enters a power-up sequence state. The ASIC 5000 then wakes up the communications module 5040. The communications module 5040 is initialized and a power-on self-test is triggered. The power-on self-test can include the ASIC 5000 communicating with the communications module 5040 using a specified sequence of reading and writing data to verify that the memory and one-time programmable memory are not corrupted.

[0144] When the ASIC 5000 first enters measurement mode, an insertion detection sequence is executed to verify that the sensor 110 is properly attached to the patient's body before proper measurements can be taken. Initially, the sensor 110 interprets a command to initiate the measurement configuration process, placing the ASIC 5000 in measurement command mode. Next, the sensor 110 briefly enters a measurement lifecycle state in which it performs several consecutive measurements to test for successful insertion. The communications module 5040 or the ASIC 5000 evaluates the measurement results to determine successful insertion. If insertion is deemed successful, the sensor 110 enters the measurement state, where it begins taking periodic measurements using the sensing hardware 5060. If the sensor 110 determines that insertion was not successful, it is triggered to enter an insertion failure mode, in which the ASIC 5000 is instructed to return to storage mode, and the communications module 5040 simultaneously disables itself.

[0145] 1A further illustrates an exemplary operating environment for providing over-the-air ("OTA") updates for use with the technology described herein. An operator of the analyte monitoring system 100 can package updates to the data receiving device 120 or sensor 110 into updates to an application running on the general-purpose data receiving device 130. Using an available communication channel between the data receiving device 120, the general-purpose data receiving device 130, and the sensor 110, the general-purpose data receiving device 130 can receive periodic updates for the data receiving device 120 or sensor 110 and initiate installation of these updates on the data receiving device 120 or sensor 110. Applications that enable the general-purpose data receiving device 130 to communicate with the analyte sensor 110, the data receiving device 120, and / or a remote application server 150 can update software or firmware on the data receiving device 120 or sensor 110 without wide-area networking capabilities, thereby allowing the general-purpose data receiving device 130 to act as an installation or update platform for the data receiving device 120 or sensor 110.

[0146] As embodied herein, a remote application server 150 operated by the manufacturer of the analyte sensor 110 and / or the operator of the analyte monitoring system 100 can provide software and firmware updates to the devices in the analyte monitoring system 100. In certain embodiments, the remote application server 150 can provide the latest software and firmware to the user device 140 or directly to the general-purpose data receiving device. As embodied herein, the remote application server 150 can provide application software updates to the application storefront server 160 using an interface provided by the application storefront. The general-purpose data receiving device 130 can periodically communicate with the application storefront server 160 to download and install updates.

[0147] After the multipurpose data receiving device 130 downloads an application update including a firmware or software update for the data receiving device 120 or the sensor 110, the data receiving device 120 or the sensor 110 and the multipurpose data receiving device 130 establish a connection. The multipurpose data receiving device 130 determines that a firmware or software update is available for the data receiving device 120 or the sensor 110. The multipurpose data receiving device 130 can provide the software or firmware update for transmission to the data receiving device 120 or the sensor 110. As an example, the multipurpose data receiving device 130 can compress or split data related to the software or firmware update, encrypt or decrypt the firmware or software update, or perform integrity checking on the firmware or software update. The multipurpose data receiving device 130 sends data related to the firmware or software update to the data receiving device 120 or the sensor 110. Additionally, the multipurpose data receiving device 130 can send instructions to initiate the update to the data receiving device 120 or the sensor 110. Additionally or alternatively, the multipurpose data receiving device 130 can provide a notification to its user and include instructions to facilitate the update, such as instructions to keep the data receiving device 120 and the multipurpose data receiving device 130 connected to and nearby a power source until the update is complete.

[0148] The data receiving device 120 or sensor 110 receives data for the update and a command to initiate the update from the multipurpose data receiving device 130. The data receiving device 120 can then install the firmware or software update. To install the update, the data receiving device 120 or sensor 110 can place itself in or resume in a so-called "safe" mode, which has only limited operational capabilities. Once the update is complete, the data receiving device 120 or sensor 110 re-enters or resets in a standard operational mode. The data receiving device 120 or sensor 110 can perform one or more self-diagnostic tests to determine that the firmware or software update was successfully installed. The multipurpose data receiving device 130 can receive notification of a successful update. The multipurpose data receiving device 130 can then report confirmation of the successful update to the remote application server 155.

[0149] In certain embodiments, the storage memory 5030 of the sensor 110 includes one-time programmable (OTP) memory. The term OTP memory can refer to memory that includes access restrictions and security to facilitate writing to specific addresses or segments within the memory a predetermined number of times. The memory 5030 can be pre-organized into multiple pre-allocated memory blocks or memory bins. The bins are pre-allocated to a fixed size. When the storage memory 5030 is one-time programmable memory, the bins can be considered to be in a non-programmable state. Additional bins that have not yet been written can be made programmable or writable. Containerizing the storage memory 5030 in this manner can improve the portability of code and data to be written to the storage memory 5030. Updating software of a device (e.g., a sensor device described herein) stored in OTP memory can be accomplished by replacing only the code in one or more specific bins that were previously written with the latest code written to one or more new bins, rather than replacing all of the code in the memory. In a second embodiment, the memory is not pre-organized. Instead, the space allocated to the data is dynamically allocated or determined as needed. Piecewise updates can be issued because containers of various sizes can be defined in which updates are expected.

[0150] 16 illustrates an exemplary operational and data flow diagram for over-the-air (OTA) programming of the storage memory 5030 in the sensor device 100 in accordance with the subject matter of the present disclosure, as well as the use of the memory during execution of processes by the sensor device 110 after OTA programming. In the exemplary OTA programming 500 illustrated in FIG. 5, a request to initiate OTA programming (or reprogramming) is sent from an external device (e.g., the data receiving device 130). At 511, the communication module 5040 of the sensor device 110 receives an OTA programming command. The communication module 5040 sends the OTA programming command to the microcontroller 5010 of the sensor device 110.

[0151] After receiving the OTA programming command, the microcontroller 5010 verifies the authenticity of the OTA programming command at 531. For example, the microcontroller 5010 may determine whether the OTA programming command is signed with an appropriate digital signature token. Upon determining that the OTA programming command is authentic, the microcontroller 5010 may place the sensor device in an OTA programming mode. At 532, the microcontroller 5010 may verify the authenticity of the OTA programming data. At 533, the microcontroller 5010 may reset the sensor device 110 to reinitialize the sensor device 110 in the programming state. Once the sensor device 110 transitions to the OTA programming state, the microcontroller 5010 may begin writing data to the rewritable memory 540 (e.g., memory 5020) of the sensor device at 534 and may further write data to the OTP memory 550 (e.g., storage memory 5030) of the sensor device at 535. The data written by the microcontroller 5010 may be based on the verified OTA programming data. The microcontroller 5010 may write data to mark one or more programming blocks or programming areas of the OTP memory 550 as invalid or inaccessible. The data written to the free or unused portions of the OTP memory can be used to replace the invalid or inaccessible programming blocks of the OTP memory 550. After the microcontroller 5010 writes the data to the respective memories at 534 and 535, it can perform one or more software integrity checks to ensure that no errors were introduced into the programming blocks during the writing process. After it can determine that the data was written without error, the microcontroller 5010 can resume normal operation of the sensor device.

[0152] In the execution mode, the microcontroller 5010 can retrieve 536 a programming manifest or programming profile from the rewritable memory 540. The programming manifest or programming profile can include a list of legal software programming blocks and can further include program execution guidelines for the sensor 110. By following the programming manifest or programming profile, the microcontroller 5010 can determine which memory blocks in the OTP memory 550 are appropriate to execute and can avoid executing or referencing expired or otherwise deemed invalid programming blocks. At 537, the microcontroller 5010 can selectively retrieve memory blocks from the OTP memory 550. At 538, the microcontroller 5010 can use the retrieved memory blocks by executing programming code stored in the memory or using stored variables.

[0153] As embodied herein, a first layer of security for communications between the analyte sensor 110 and other devices can be established based on security protocols dictated by and embedded in the communications protocol used for communication. Another layer of security can be based on communications protocols requiring proximity of the communicating devices. Additionally, certain packets and / or certain data encapsulated therein can be encrypted, while other packets and / or other data within the packets may or may not be otherwise encrypted. Additionally or alternatively, application layer encryption can be used in conjunction with one or more block or stream ciphers to establish mutual authentication and communications encryption with other devices in the analyte monitoring system 100.

[0154] The ASIC 5000 of the analyte sensor 110 can be configured to dynamically generate authentication and encryption keys using data maintained in the storage memory 5030. The storage memory 5030 can be pre-programmed with a set of valid authentication and encryption keys for use with a particular class of device. The ASIC 5000 can be further configured to perform an authentication procedure with other devices using received data and apply the generated key to the sensitive data before transmitting the sensitive data. The generated key can be unique to the analyte sensor 110, unique to a pair of devices, unique to a communication session between the analyte sensor 110 and another device, unique to a message sent during the communication session, or unique to a data block enclosed in the message.

[0155] Both the sensor 110 and the data receiving device 120 can vouch for the authority of the other party in a communication session, for example, to issue commands or receive data. In certain embodiments, identity authentication can be performed through two mechanisms. First, the party asserting identity provides a valid certificate signed by the device manufacturer or the operator of the analyte monitoring system 100. Second, authentication can be performed using public and private keys established by the device in the analyte monitoring system 100 or by the operator of the analyte monitoring system 100, and a shared secret derived therefrom. To verify the identity of the other party, the party can provide proof that it has control of the private key.

[0156] The manufacturer of the analyte sensor 110, the data receiving device 120, or the provider of the application for the general-purpose data receiving device 130 can provide the information and programming necessary for these devices to communicate securely through secure programming and updates. For example, the manufacturer can provide information that can be used to generate cryptographic keys (e.g., entropy-based random values) for each device, including a secure root key for the analyte sensor 110 and optionally the data receiving device 120, which can be used in combination with device-specific information and operational data to generate unique cryptographic values ​​for the device, session, or data transmission as needed.

[0157] Analyte data associated with a user is sensitive data due, at least in part, to its potential use for a variety of purposes, including health monitoring and drug dosage determination. In addition to user data, the analyte monitor system 100 can implement security hardening against attempts by outsiders to reverse engineer it. Communication connections can be encrypted using device-specific or session-specific encryption keys. Encrypted or unencrypted communications between any two devices can be verified using transmission integrity checks built into the communications. Analyte sensor 110 operation can be protected from tampering by restricting access to read and write functionality to the memory 5020 through the communication interface. The sensor can be configured to allow access only to known or “trusted” devices listed in a “whitelist” or devices that can provide a predetermined code associated with the manufacturer or other authorized user. The whitelist may represent a limited scope, meaning that no connection identifiers other than those included therein may be used, or a preferred scope in which the whitelist is searched first, but other devices may still be used. Additionally, the sensor 110 can reject or block a connection request if the requestor fails to complete the login procedure over the communication interface within a predetermined time period (e.g., within 4 seconds). These features provide protection against certain denial of service attacks, particularly those directed against the BLE interface.

[0158] As embodied herein, the analyte monitoring system 100 may employ periodic key rotation to further reduce key revocation and tampering. The key rotation strategy employed by the analyte monitoring system 100 may be designed to accommodate backward compatibility for devices deployed or distributed at a site. As an example, the analyte monitoring system 100 may employ keys designed to be compatible with multiple generations of keys used by upstream devices for downstream devices (e.g., that are on site or that cannot provide updates in a feasible manner).

[0159] For purposes of illustration and not limitation, reference is made to an exemplary embodiment of a message sequence diagram 600 for use with the subject matter of the present disclosure, shown in FIG. 17 and specifying an exemplary data interaction between a pair of devices, specifically a sensor 110 and a data receiving device 120. The data receiving device 120 may be a data receiving device 120 or a general-purpose data receiving device 130, as embodied herein. In step 605, the data receiving device 120 may send a sensor wake-up command 605 to the sensor 110, for example, via a short-range communication protocol. The sensor 110 may be primarily dormant prior to step 605, conserving battery power until a full wake-up is required. During step 610 after wake-up, the sensor 110 may collect data or perform other operations appropriate to the sensing hardware 5060 of the sensor 110. In step 615, the data receiving device 120 may initiate an authentication request command 615. In response to the authentication request command 615, both the sensor 110 and the data receiving device 120 can engage in a mutual authentication process 620. The mutual authentication process 620 can include the transfer of data including challenge parameters that enable the sensor 110 and the data receiving device 120 to ensure that the other device is sufficiently capable to adhere to the agreed-upon security framework described herein. Mutual authentication can be based on the ability of two or more entities to authenticate each other, verifying the establishment of a secret key through a challenge response with or without the involvement of an online trusted third party. Mutual authentication can be performed using two-, three-, four-, or five-pass authentication, or similar versions thereof.

[0160] Following a successful mutual authentication process 620, in step 625, the sensor 110 can provide a sensor secret 625 to the data receiving device 120. The sensor secret includes a sensor-specific value and can be derived from a random value generated during manufacturing. The sensor secret can be encrypted before or during transmission to prevent third parties from accessing it. The sensor secret 625 can be encrypted by one or more of the keys generated by the mutual authentication process 620 or accordingly. In step 630, the data receiving device 120 can derive a sensor-specific encryption key from the sensor secret. The sensor-specific encryption key can further be session-specific. Thus, the sensor-specific encryption key can be determined by each device without being transmitted between the sensor 110 and the data receiving device 120. In step 635, the sensor 110 can encrypt data to be included in the payload. In step 640, the sensor 110 can transmit the encrypted payload 640 to the data receiving device 120 using the communication link established between its appropriate communication model and the appropriate communication model of the data receiving device 120. In step 645, the data receiving device 120 can decrypt the payload using the sensor-specific encryption key derived during step 630. Following step 645, the sensor 110 can send additional data (including newly collected data), and the data receiving device 120 can process the received data appropriately.

[0161] As discussed herein, the sensor 110 may be a device with only limited processing capabilities, battery power, and storage capacity. The encryption techniques (e.g., selection of cryptographic algorithms or implementations thereof) used by the sensor 110 may be selected based at least in part on these limitations. The data receiving device 120 may be a more powerful device with fewer limitations of this nature. Thus, the data receiving device 120 may use more sophisticated and computationally intensive encryption techniques, such as cryptographic algorithms and implementations.

[0162] The analyte sensor 110 can be configured to modify its discoverability behavior to attempt to increase the probability that a receiving device receives a proper data packet and / or reduce other limitations that may result in the lack of the ability to provide or receive an acknowledgment signal. Modifying the discoverability behavior of the analyte sensor 110 can include, by way of example and not limitation, modifying how often connection data is included in data packets, modifying how often data packets are transmitted in general, lengthening or shortening the broadcast window for data packets, modifying the amount of time the analyte sensor 110 waits to receive an acknowledgment or scanning signal after a broadcast that includes directional communication (e.g., via one or more trial transmissions) to one or more devices that may have previously communicated with the analyte sensor 110 and / or one or more devices on a whitelist, modifying the transmit power for the communications module when broadcasting a data packet (e.g., to increase the broadcast distance or consume less energy to extend the battery life of the analyte sensor), modifying the rate at which data packets are prepared and broadcast, or a combination of one or more other modifications. Additionally or alternatively, the receiving device may also adjust parameters related to the device's listen behavior to increase the likelihood of receiving data packets containing connection data.

[0163] As embodied herein, the analyte sensor 110 can be configured to broadcast data packets using two types of windows. The first window refers to the rate at which the analyte sensor 110 is configured to activate its communications hardware. The second window refers to the rate at which the analyte sensor 110 is configured to actively transmit (e.g., broadcast) data packets. By way of example, the first window may indicate that the analyte sensor 110 activates its communications hardware to transmit and / or receive data packets (including connection data) during the first two seconds of each 60-second period. The second window may indicate that the analyte sensor 110 transmits a data packet every 60 milliseconds during each two-second window. For the remainder of the two-second window, the analyte sensor 110 is scanning. The analyte sensor 110 can extend or shorten either window to modify its discoverability behavior.

[0164] In certain embodiments, the discoverability behavior of the analyte sensor may be stored in a discoverability profile, and modifications may be made based on one or more factors, such as the status of the analyte sensor 110, and / or by applying rules based on the status of the analyte sensor 110. For example, these rules may reduce the power consumed by the broadcast process for the analyte sensor 110 when the battery level of the analyte sensor 110 drops below a predetermined amount. As another example, configuration settings for broadcasting or otherwise transmitting packets may be adjusted based on the ambient temperature, the temperature of the analyte sensor 110, or the temperature of certain components of the analyte sensor 110's communications hardware. In addition to modifying transmission power, other parameters related to the transmission function or transmission process of the analyte sensor 110's communications hardware may be modified, including, but not limited to, the rate, frequency, and timing of transmission. As another example, when analyte data indicates that a subject is experiencing or about to experience an adverse health event, the rules described above may increase the discoverability of the analyte sensor 110 to alert receiving devices of this adverse health event.

[0165] As embodied herein, certain calibration functions for the sensing hardware 5060 of the analyte sensor 110 can be adjusted based on a function of the external or internal environment, and also to compensate for natural degradation of the sensing hardware 5060 during extended periods of non-use (e.g., a "shelf life" before use). The calibration functions of the sensing hardware 5060 can be adjusted automatically by the sensor 110 (e.g., by operation of the ASIC 5000 which modifies functions in the memory 5020 or storage 5030) or can be adjusted by other devices in the analyte monitoring system 100.

[0166] By way of example, the sensor sensitivity of the sensing hardware 5060 can be adjusted based on external temperature data or time since manufacture. If the external temperature is monitored during sensor storage, the presently disclosed subject matter can adaptively change the sensor sensitivity compensation over time as the device experiences changes in storage conditions. By way of example and not limitation, adaptive sensitivity adjustment can be performed using an “active” storage mode in which the analyte sensor 110 is periodically woken to measure temperature. These features can conserve the battery of the analyte device and extend the life of the analyte sensor. At each temperature measurement, the analyte sensor 110 can calculate a sensitivity adjustment amount over that period based on the measured temperature. The temperature-weighted adjustment amounts can then be accumulated over the active storage mode period to calculate a total sensor sensitivity adjustment value at the end of the active storage mode (e.g., upon insertion). Similarly, upon insertion, the sensor 110 can determine the time difference between its own or the sensing hardware 5060's manufacturing time (which can be written to the ASIC 5000's storage 5030) and modify the sensor sensitivity or other calibration functions according to one or more known natural degradation rates or natural degradation formulas.

[0167] Additionally, for purposes of illustration and not limitation, as embodied herein, the sensor sensitivity adjustment can account for other sensor conditions, such as sensor drift. For example, in the event of sensor drift, the sensor sensitivity adjustment can be hard-coded into the sensor 110 during manufacturing based on an estimate of how much an average sensor is expected to drift. The sensor 110 can use a calibration function having a time-varying function for the sensor's offset and gain that can account for drift over its wear period. Thus, the sensor 110 can account for the sensor's 110 drift over time, represent the sensor's sensitivity, and utilize a device-dependent function, which can be device-specific, in combination with a baseline glucose profile to convert interstitial current to interstitial glucose. Such a function that accounts for sensor sensitivity and drift can improve the accuracy of the sensor 110 over wear periods without requiring user calibration.

[0168] The sensor 110 detects raw measurements from the sensing hardware 5060. On-sensor processing can be performed, such as by one or more models trained to interpret the raw measurements. The models can be machine learning models trained off-device to detect, predict, or interpret the raw measurements to detect, predict, or interpret one or more analyte levels. Additional trained models can be activated based on the output of the machine learning models trained to interact with the raw measurements. By way of example, these models can be used to detect, predict, or recommend events based on the raw measurements and the type of analyte detected by the sensing hardware 5060. Events can include the initiation or completion of physical activity, a meal, the application of a medical procedure or medication, an emergency health event, and other events of a similar nature.

[0169] The model may be provided to the sensor 110, data receiving device 120, or general-purpose data receiving device 130 during manufacturing or during firmware or software updates. The model may be periodically refined by the sensor 110 manufacturer, the operator of the analyte monitoring system 100, or others, based on data received from the sensors 110 and data receiving devices of individual users or multiple users collectively. In certain embodiments, the sensor 110 includes sufficient computer components to support further training or refinement of the machine learning model based, for example, on the unique capabilities of the user to which it is attached. Machine learning models may include, by way of example and not limitation, models trained using or incorporating decision tree analysis, gradient boosting, adaptive boosting, artificial neural networks or variants thereof, linear discriminant analysis, nearest neighbor analysis, support vector machines, supervised or unsupervised classification, and others. In addition to machine learning models, models may include algorithmic or rule-based models. Model-based processing may be performed by other devices, including the data receiving device 120 or general-purpose data receiving device 130, upon receiving data from the sensor 110 (or other downstream devices).

[0170] Data transmitted between the sensor 110 and the data receiving device 120 may include raw or processed measurements. Data transmitted between the sensor 110 and the data receiving device 120 may further include alarms or notifications for display to a user. The data receiving device 120 may display or otherwise communicate notifications to a user based on the raw or processed measurements, or may display alarms when received from the sensor 110. Alarms that can be triggered for display to a user include alarms based on direct analyte values ​​(e.g., a transient reading that exceeds or fails to meet a threshold), trends in analyte values ​​(e.g., average reading that exceeds or fails to meet a threshold over a set period of time, slope), predictions of analyte values ​​(e.g., when an algorithmic calculation based on the analyte value exceeds or fails to meet a threshold), sensor alerts (e.g., detection of a suspected malfunction), communication alerts (e.g., absence of communication between the sensor 110 and the data receiving device 120 for a threshold period of time, an unknown device attempting or failing to initiate a communication session with the sensor 110), reminders (e.g., reminders to charge the data receiving device 120, reminders to take medication or perform other activities), and other alerts of a similar nature. By way of example and not limitation, as embodied herein, the alarm parameters described herein can be configurable by the user, or can be fixed during manufacturing or a combination of user-configurable and non-user-configurable parameters.

[0171] The term "reference electrode" as used herein can refer to either a reference electrode or an electrode that functions as both a reference electrode and a counter electrode. Similarly, the term "counter electrode" as used herein can refer to both a counter electrode and a counter electrode that also functions as a reference electrode.

[0172] The sensor 110 described herein can include a sensing element including one or more electrodes configured to detect one or more analyte levels in a bodily fluid, examples of which are shown in FIGS. 18A-20. The one or more electrodes can include one or more enzyme-responsive elements. For example, as embodied herein, the sensor 110 can detect lactate levels in a bodily fluid. In another example, the sensor 110 can detect lactate levels and glucose levels in a bodily fluid. In yet another example, the sensor 110 can detect lactate levels and ketone levels in a bodily fluid. The sensor 110 can include one working electrode capable of detecting lactate and / or another working electrode capable of detecting glucose, ketone, alcohol, and / or any other analyte levels. In some examples, the sensor 110 can include two or more sensing elements configured to detect two or more analyte levels in a bodily fluid. The sensor 110 may also be referred to as an "analyte sensor."

[0173] A display unit of the sensor or reader device can be used to provide instructions, suggestions, guides, recommendations, and / or any other output associated with or corresponding to the lactate concentration. Appropriate processing algorithms, processors, memory, electronic components, etc. can reside in either a trusted computer system, a remote terminal, a cloud server, the reader device, and / or the housing for the sensor itself. The guides, recommendations, and / or output, etc. can be shown on a display unit or graphical user interface in electronic communication with one or more components of the sensor or sensor system. The display unit or display device can be a dedicated reader device or a user device such as a mobile device. Alternatively, the display unit or display device can be a third-party server, a cloud server, or a remote terminal that communicates with various software applications accessible to medical professionals. The dedicated reader device, the user device, or one of the aforementioned servers can further communicate the data or output to a smart home device, a wearable watch or device, a personal health monitor, etc.

[0174] As embodied herein, a reader device may include a processor, memory, an input / output interface, and a communication interface. The processor includes hardware for executing instructions, such as those making up a computer program. By way of example and not limitation, to execute instructions, a processor may retrieve (or fetch) instructions from an internal register, an internal cache, memory, or storage, execute those instructions, and then write one or more results to an internal register, an internal cache, memory, or storage. The processor may include one or more internal caches for data, instructions, or addresses. The one or more processors may include one or more arithmetic logic units (ALUs) or be multi-core processors.

[0175] As embodied herein, memory includes a main memory for storing instructions for a processor to execute or data on which the processor operates. By way of example and not limitation, a reader device may load instructions into memory from storage or another source. The processor may then load the instructions from memory into an internal register or cache. To execute the instructions, the processor may retrieve and decode the instructions from the internal register or cache. During or after executing the instructions, the processor may write one or more results (which may be intermediate or final results) to the internal register or cache. The processor may then write one or more of these results to memory. For example, the memory may include random access memory (RAM). This RAM may be volatile memory, dynamic RAM (DRAM), or static RAM (and SRAM). The RAM may be single-ported RAM or multi-ported RAM, and the memory may include one or more memories.

[0176] As described herein, with reference to FIG. 1A , the sensor 110 can be at least partially inserted into the dermis or subcutaneous layer of the skin. The sensor 110 can include a sensor tail of sufficient length for insertion to a desired depth into interstitial fluid. The sensor tail can include at least one working electrode and one or more active areas (sensing regions / spots or sensing layers) positioned thereon that sense lactate (or in some cases, one or more additional analytes). For example, the active area can be in the form of one or more individual spots. The number of individual spots can range, for example, from one spot to several tens of spots. The one or more individual spots can range in area from about 0.01 square millimeters (mm) to about 1.00 mm, e.g., from about 0.1 mm to about 0.5 mm, from about 0.25 mm to about 0.75 mm, from about 0.05 mm to about 0.2 mm, or any other smaller or larger value.

[0177] One or more active areas can include one or more enzymes used to facilitate lactate detection. The active area can include, for example, a polymeric material to which one or more of these enzymes are chemically bonded (e.g., covalently, ionically, and the like) or otherwise immobilized (e.g., free in a matrix). For example, each active area can be externally coated with a mass-limited biocompatible thin film and / or an electron transfer agent to facilitate at least lactate detection.

[0178] As embodied herein, lactate levels can be monitored in any biological fluid of interest, such as dermal fluid, interstitial fluid, plasma, blood, lymphatic fluid, synovial fluid, cerebrospinal fluid, saliva, bronchoalveolar lavage fluid, or amniotic fluid.

[0179] As shown in FIG. 1A , the sensor control unit 102 can manually or automatically communicate data acquired using the sensor 110 to the reader device 120. For example, lactate concentration data can be communicated automatically or periodically after a predetermined period of time has elapsed, with the data stored in memory until transmission (e.g., every few seconds, every minute, every five minutes, or another predetermined period of time). The sensor control unit 102 can communicate with the reader device 120 based on a wearer or user's action or request rather than according to a set schedule. For example, data can be communicated from the sensor control unit 102 using NFC or RFID technology when the sensor electronics are brought within communication range of the reader device 120. Additionally or alternatively, Bluetooth can be used to facilitate communication of data from the sensor control unit 102 to the reader device 120. The data can remain stored in the memory of the sensor control device 102 until communicated to the reader device 120. In one example, data can be stored in the memory of the sensor control device 102 for up to eight hours. In other examples, the data may be stored for up to 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 10 hours, 12 hours, 24 hours, or any other number of hours. The data may then be transmitted from the sensor control device 102 to the reader device 120 when the sensor control device 102 comes within a given distance from the reader device 120.

[0180] The various electrodes can be at least partially stacked or layered on one another. For example, the various electrodes can be laterally spaced apart from one another on the sensor tail. Similarly, the associated active areas on each electrode can be vertically stacked or laterally spaced apart from one another. The various electrodes can be insulated from one another by a dielectric material or similar insulator.

[0181] For purposes of illustration and not limitation, reference is now made to FIG. 18, which illustrates a diagram of changes in blood lactate levels at different zones, which may correspond, for example, to different training zones for an athlete. For illustrative purposes only, the X-axis represents the athlete's running speed, ranging from 16 km / h to 23 km / h. The Y-axis represents blood lactate levels, ranging from 0 mm to 14 mm, generated by an exemplary analyte sensor in accordance with the presently disclosed subject matter. According to the different blood lactate levels corresponding to different running speeds, this diagram can be divided into different monitoring or training zones for the athlete. Additionally or alternatively, lactate levels can be used to determine and monitor sepsis.

[0182] By way of example and not limitation, this diagram may show a user's lactate level curve and provide the user with various metrics, including, but not limited to, lactate threshold 1 (LT1) and lactate tipping point (LTP, also referred to as LT2). Determining LT1 and LTP may allow athletes and their coaches to properly determine different training zones. By way of example and not limitation, in a seven-zone system used by endurance athletes, zones 1 and 2 (labeled "Endurance" in FIG. 18) are below LT1 and range in speed from approximately 17 km / h to approximately 19.5 km / h. Corresponding blood lactate levels range from approximately 2 mmH to approximately 3 mmH. Zone 3 (labeled "Constant Speed" in FIG. 18) is between LT1 and LTP and ranges in speed from approximately 19.5 km / h to approximately 21 km / h. Corresponding blood lactate levels range from approximately 3 mmH to approximately 6 mmH. Zones 4-6 (labeled "high intensity") are not greater than LTP, and speeds range from approximately 21 km / h to 22.5 km / h. Zone 7 (not shown) illustrates explosive force effects using a phosphagen system that may be less desirable for inclusion in a lactate monitoring system. However, due at least in part to the belief that analyte sensor power generation and lactate levels do not closely correspond to one another during individual wear, delay correction can be performed to obtain monitored blood lactate levels. Thus, by way of example and not limitation, systems and devices according to the presently disclosed subject matter can perform delay correction to more accurately determine monitored lactate levels in order to determine an athlete's fitness level and / or fitness improvement during training (or fitness decline due to undertraining, overtraining, or injury). Additionally or alternatively, delay correction can be performed automatically by analyte sensor systems and devices, particularly to assist users experiencing certain conditions that prevent them from manually correcting or calibrating the sensor.By way of example and not limitation, as embodied herein, a system can be programmed to not display data to a user unless or until a certain amount of exercise, e.g., one minute of exercise, is completed. Additionally or alternatively, the systems and devices disclosed herein can provide personalized recommendations based on an analysis of lactate levels. For example, the systems and devices can determine or identify a user's lactate threshold based on information obtained during exercise.

[0183] For purposes of illustration and not limitation, reference is now made to FIG. 19. FIG. 19 illustrates an exemplary diagram showing different response delays to changes in blood lactate for different analyte sensors located proximate the subcutaneous insertion site of the same user. The curves represent different raw current signals corresponding to time from sensor activation. The exemplary sensors (S2 and S3) may be worn by the same user on the right arm. Additionally, "Ven YSI" represents the venous blood baseline profile for lactate levels. For purposes of illustration and not limitation, exemplary sensor S2 lags slightly behind the baseline by around 9.93 minutes, while sensor S3 has a longer delay spanning around 33 minutes. Thus, delay compensation performed by the analyte sensor system can be advantageous in adapting ISF sensor results to changes in blood lactate levels.

[0184] For purposes of illustration and not limitation, reference is now made to FIG. 20 , which illustrates an exemplary process (2000) for performing delay compensation in an exemplary analyte sensor system. For purposes of illustration and not limitation, high-intensity exercise may be exercise that stimulates an athlete to have a blood lactate level of 6 mM or greater. As embodied herein, an exemplary system according to the presently disclosed subject matter performing exemplary processing may include various measurements, such as temperature and acceleration measurements, to indicate that high-intensity exercise has begun. In step 2001, the athlete begins a high-intensity exercise (t=0). In step 2005, the athlete completes the exercise and a lower-intensity warm-up and rests (t=t1). The analyte sensor measures the corresponding lactate level in the ISF. Thereafter, the analyte sensor continues to track the ISF lactate level. In step 2015, the analyte sensor identifies a second lactate response in the ISF corresponding to a second time (t=t2). At step 2020, the analyte sensor system may calculate a correction parameter to perform a correction on the measured lactate level. As embodied herein, the correction parameter may be a delay time. By way of example and not limitation, the delay time may be a mathematical function based on t1 and t2. The delay time represents how much time it takes the sensor to detect a sudden increase in the lactate level. For example, the delay time τ may be equal to f(t1, t2). At step 2025, the analyte sensor system may perform a delay correction based on the correction parameter, e.g., the delay time τ.

[0185] As embodied herein, for purposes of illustration and not limitation, the correction performed can be a linear correction model based on the rate of change of the measured lactate level. For example, the analyte sensor system can obtain and generate the rate of change of the measured lactate level from the analyte sensor. The rate of change can be the first time derivative of the measured lactate level. As embodied herein, the linear correction model can include an intercept b, which can be sensor dependent. The analyte sensor system can perform the correction according to the relationship Cr = τ(dC / dt) + b, where Cr represents the calculated delay correction and dC / dt represents the rate of change.

[0186] Additionally or alternatively, the systems and devices disclosed herein can provide personalized recommendations based on an analysis of lactate levels, for example, the systems and devices can determine and identify a level or intensity of exercise that a user can sustain without exceeding their lactate threshold.

[0187] For purposes of illustration and not limitation, reference is now made to FIG. 21 , which illustrates an exemplary diagram showing different response delays to blood lactate changes after correction for different analyte sensors located proximate the subcutaneous insertion site of the same user. These curves represent different raw current signals corresponding to time from sensor activation. The exemplary sensors (S2 and S3) can be worn by the same user on the right arm. Furthermore, “Ven YSI” represents the venous blood baseline profile for lactate levels. For purposes of illustration and not limitation, exemplary sensor S2 closely matches the baseline profile during the 164th to 165th hour of wear, whereas sensor S3 has a slight delay of approximately 5 minutes after correction compared to the baseline level. Therefore, automatic sensor delay correction can improve sensor performance with greater accuracy for blood lactate levels.

[0188] For purposes of illustration and not limitation, reference is now made to FIG. 22, which illustrates an exemplary diagram showing lactate level changes during high-intensity exercise to determine delay time τ. For purposes of illustration and not limitation, the X-axis represents time from the start of exercise. The Y-axis represents lactate levels in the ISF. High-intensity exercise can include, for example, cycling, swimming, running, rowing, etc. Exercise duration can range from 30 seconds up to 2 minutes, preferably 30 seconds to 1 minute. The athlete will exercise at or near peak intensity for this duration to ensure a rapid increase in lactate production to determine the delay time for correction. During exercise, the heart rate will approach a maximum value (e.g., 170-200 beats per minute for an adult, depending on age and fitness). For purposes of illustration, the exercise will involve large muscle groups, including the quadriceps, to maximize lactate production for accuracy. In elite athletes, one minute of all-out effort can result in lactate peaking above 7 mM and even above 15 mM in the blood and ISF, as shown in Figure 8. In amateur athletes and the general population who exercise less frequently, lactate may peak above 4 mM. For illustrative purposes, the curve in Figure 22 illustrates that there is a delay time of around 8 minutes for an elite athlete whose lactate level peaks above 15 mM. The delay time can be determined and used to automatically perform delay compensation for an analyte sensor system according to the presently disclosed subject matter.

[0189] While the presently disclosed subject matter has been described herein with respect to certain preferred embodiments, those skilled in the art will recognize that various modifications and improvements can be made to these subject matter without departing from the scope of the presently disclosed subject matter. Furthermore, although individual features of one embodiment of the presently disclosed subject matter may be discussed and illustrated in this specification with one such embodiment and not discussed or illustrated in other embodiments, it should be apparent that individual features of one embodiment can be combined with one or more features of another embodiment or with features from multiple embodiments.

[0190] In addition to the specific embodiments claimed below, the presently disclosed subject matter also relates to other embodiments having any other possible combinations of the dependent features claimed below and those disclosed above. That is, the specific features provided in the dependent claims and those disclosed above can be combined with each other in other ways within the presently disclosed subject matter, and therefore, it should be recognized that the presently disclosed subject matter also specifically relates to other embodiments having any other possible combinations. That is, the above description of specific embodiments of the presently disclosed subject matter has been provided for purposes of illustration and description. This description is not intended to be exhaustive or to limit the presently disclosed subject matter to the disclosed embodiments.

[0191] It will be apparent to those skilled in the art that various modifications and variations can be made in the methods and systems of the presently disclosed subject matter without departing from the spirit or scope of the presently disclosed subject matter. Thus, the presently disclosed subject matter is intended to cover modifications and variations that come within the scope of the appended claims and their equivalents.

[0192] Also disclosed are the following clauses: 1. An analyte monitor device including one or more processors, an analyte sensor, a communications module, and one or more memories communicatively coupled to the one or more processors, the analyte sensor, and the communications module, wherein the one or more processors are configured to: generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a first time; generate analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a second time; calculate correction parameters based on the analyte data corresponding to the first time and the analyte data corresponding to the second time; and perform delay correction using at least the calculated correction parameters to obtain the monitored analyte level. 2. The analyte monitor device of clause 1, wherein the one or more processors are further configured to calculate a rate of change of the monitored analyte level based on analyte data measured by the analyte sensor. 3. The analyte monitor device of clause 1, wherein the one or more processors are configured to perform lag correction on the analyte levels monitored during the user's exercise period. 4. The analyte monitor device of clause 3, wherein the exercise period includes a period of high-intensity exercise. 5. The analyte monitor device of clause 1, wherein the analyte sensor is inserted subcutaneously into the bodily fluid of the user. 6. The analyte monitor device of clause 5, wherein the bodily fluid comprises blood or interstitial fluid. 7. The analyte monitor device of clause 1, wherein the correction parameter includes a delay time calculated based on the first time and the second time. 8. The analyte monitor device of clause 7, wherein delay correction is performed using a linear correction model. 9. The analyte monitor device of clause 8, wherein delay correction is performed using a linear correction model, the correction equal to an intercept added to the product of the calculated delay time multiplied by the rate of change of the monitored analyte level based on the analyte data measured by the analyte sensor. 10. The analyte monitor device of clause 9, wherein the intercept depends on the analyte sensor. 11. The analyte monitor device of clause 1, wherein delay compensation includes compensating for a delay between a change in the monitored analyte level in the interstitial fluid and a change in the monitored analyte level in the blood. 12. The analyte monitor device of clause 1, further comprising a display configured to receive and display the monitored analyte level. 13. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of an analyte monitoring system, cause the analyte monitoring system to generate analyte data indicative of a monitored analyte level measured by an analyte sensor corresponding to a first time, generate analyte data indicative of a monitored analyte level measured by an analyte sensor corresponding to a second time, calculate a correction parameter based on the analyte data corresponding to the first time and the analyte data corresponding to the second time, and perform a delay correction using at least the calculated correction parameter to obtain a monitored analyte level. 14. The computer-readable medium of clause 13, further comprising instructions for calculating a rate of change of a monitored analyte level based on analyte data measured by the analyte sensor. 15. The computer-readable medium of clause 13 containing instructions for performing a lag correction on analyte levels monitored during a user's exercise period. 16. The computer-readable medium of clause 15, wherein the exercise period includes a period of high-intensity exercise. 17. The computer-readable medium of clause 13, wherein the analyte sensor is inserted subcutaneously into a bodily fluid of a user. 18. The computer-readable medium of clause 17, wherein the bodily fluid comprises blood or interstitial fluid. 19. The computer-readable medium of clause 13, wherein the correction parameter includes a delay time calculated based on the first time and the second time. 20. The computer-readable medium of clause 19, wherein the delay correction is performed using a linear correction model. 21. The computer-readable medium of clause 20, wherein the lag correction is performed using a linear correction model, the correction being equal to an intercept added to the product of the calculated lag time multiplied by the rate of change of the monitored analyte level based on the analyte data measured by the analyte sensor. 22. The computer-readable medium of clause 21, wherein the intercept is dependent on the analyte sensor. 23. The computer-readable medium of clause 13, wherein the delay correction includes correcting for a delay between a change in the monitored analyte level in the interstitial fluid and a change in the monitored analyte level in the blood. 24. The computer-readable medium of clause 13 containing instructions for communicating the monitored analyte level to a display and displaying the monitored analyte level via the display. [Explanation of symbols]

[0193] t1 The time an athlete rests after completing exercise and low-intensity warm-up exercises t2 is the time at which the analyte sensor identifies a second lactate response in the ISF corresponding to a second time.

Claims

1. one or more processors; an analyte sensor; A communication module; one or more memories communicatively coupled to the one or more processors, the analyte sensor, and the communications module, the one or more processors comprising: generating analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a first time; generating analyte data indicative of the monitored analyte level measured by the analyte sensor corresponding to a second time; calculating a correction parameter based on the analyte data corresponding to the first time and the analyte data corresponding to the second time; and performing a delay correction using at least the calculated correction parameters to obtain the monitored analyte level. The one or more memories configured as described above; 16. A analyte monitor device comprising:

2. The one or more processors: calculating a rate of change of the monitored analyte level based on analyte data measured by the analyte sensor; Further configured as follows: The analyte monitoring device of claim 1 .

3. The analyte monitor device of claim 1 , wherein the one or more processors are configured to perform the lag correction on the monitored analyte levels during a user's exercise period.

4. The analyte monitoring device of claim 3 , wherein the exercise period comprises a period of high intensity exercise.

5. The analyte monitoring device of claim 1 , wherein the analyte sensor is inserted subcutaneously into a user's bodily fluid.

6. The analyte monitoring device of claim 5 , wherein the bodily fluid comprises blood or interstitial fluid.

7. The analyte monitoring device of claim 1 , wherein the correction parameter comprises a delay time calculated based on the first time and the second time.

8. The analyte monitoring device of claim 7 , wherein the delay correction is performed using a linear correction model.

9. A delay correction is performed using the linear correction model; the correction is equal to an intercept added to the product of the calculated delay time multiplied by the rate of change of the monitored analyte level based on analyte data measured by the analyte sensor. The analyte monitoring device of claim 8 .

10. The analyte monitoring device of claim 9 , wherein the intercept is dependent upon the analyte sensor.

11. 10. The analyte monitor device of claim 1, wherein the delay correction comprises correcting for a delay between a change in the monitored analyte level in interstitial fluid and the monitored analyte level in blood.

12. 10. The analyte monitor device of claim 1, further comprising a display configured to receive and display the monitored analyte level.

13. When executed by one or more processors of an analyte monitoring system, the analyte monitoring system comprises: generating analyte data indicative of a monitored analyte level measured by the analyte sensor corresponding to a first time; generating analyte data indicative of the monitored analyte level measured by the analyte sensor corresponding to a second time; calculating a correction parameter based on the analyte data corresponding to the first time and the analyte data corresponding to the second time; and performing a delay correction using at least the calculated correction parameters to obtain the monitored analyte level. instruction, 1. A non-transitory computer readable medium comprising:

14. calculating a rate of change of the monitored analyte level based on analyte data measured by the analyte sensor; The computer-readable medium of claim 13 further comprising instructions for:

15. performing said lag correction on said monitored analyte levels during a user's exercise period; 14. The computer readable medium of claim 13 comprising instructions for:

16. The computer-readable medium of claim 15 , wherein the exercise period comprises a period of high intensity exercise.

17. 14. The computer readable medium of claim 13, wherein the analyte sensor is inserted subcutaneously into a bodily fluid of a user.

18. 20. The computer-readable medium of claim 17, wherein the bodily fluid comprises blood or interstitial fluid.

19. The computer-readable medium of claim 13 , wherein the correction parameter comprises a delay time calculated based on the first time and the second time.

20. 20. The computer-readable medium of claim 19, wherein the delay correction is performed using a linear correction model.

21. A delay correction is performed using the linear correction model; the correction is equal to an intercept added to the product of the calculated delay time multiplied by the rate of change of the monitored analyte level based on analyte data measured by the analyte sensor.

21. The computer-readable medium of claim 20.

22. 22. The computer readable medium of claim 21, wherein the intercept is dependent on the analyte sensor.

23. 14. The computer-readable medium of claim 13, wherein the lag correction comprises correcting for a lag between a change in the monitored analyte level in interstitial fluid and the monitored analyte level in blood.

24. 14. The computer-readable medium of claim 13, comprising instructions for communicating the monitored analyte level to a display and displaying the monitored analyte level via the display.

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