Composition for dialysis solution, and sensor unit

Abstract

The invention relates to improving quality assurance during provision and use of dialysis solutions. According to the invention, precursor compositions for dialysis solutions are mixed with a coding substance and corresponding sensors are made available through the use of which the specifications of the used compositions can be ascertained by means of the coding substance and can be communicated to the treatment machine.

Description

[0001]230007WO01 Fresenius Medical Care Deutschland GmbH D-61352 Bad Homburg ^ ...In HD and HF this exchange takes place via a synthetic membrane in a dialyzer, in peritoneal dialysis via the patient's peritoneum. The typical components of such a flushing solution, generally called dialysis solution in blood purification procedures, are salts of sodium, potassium, calcium and magnesium with chloride, bicarbonate, acetate and citrate as anions and glucose. In clinical application the doctor can choose between different dialysis solutions in which the concentrations of individual components vary. The composition of the dialysis solution, i.e. the type and concentration of the substances it contains, is crucial for tolerability and therapeutic efficacy. This influence is particularly important when using therapeutic control procedures in which the composition of the dialysis solution is automatically adjusted by the machine. Increasing the efficiency of dialysis treatment with regard toThe duration of dialysis and the extent of exchange, described by clearance, increase the influence of the composition of the dialysis solution on the substance composition in the patient's blood and body water. The composition most suitable for the patient is prescribed by the doctor. The consistency of this prescription with the dialysis solution provided by the treatment machine is therefore essential for the patient's well-being. Therefore, when using or providing rinsing solution or dialysis solution on the treatment machine, effective quality assurance measures are necessary. These ensure that the correct composition is connected to the treatment machine. In addition, certain treatment procedures may have special requirements regarding the quality of the rinsing solution, and the treatment machine will only release the solution if these requirements are met. The provision of the rinsing solution or dialysis solutionThe dialysis solution can be prepared in different ways. The solution can be provided ready-to-use in bags or similar containers. This type of preparation is most commonly used in peritoneal dialysis. In HD and HF blood purification procedures, the dialysis solution is prepared continuously by mixing one or more concentrates and ultrapure water directly in the treatment machine. These concentrates can be in solid or liquid form. They can be connected in bags or canisters directly to the treatment machine and to suitable withdrawal devices. Alternatively, the concentrates can be fed from central supply lines to the individual treatment machines. The composition and the quality criteria applied during production are shown on the label on the product packaging in written form, as a barcode, or RFID tag. This label can be read by the user.Suitable reading devices on the treatment device can read the information and compare it with the respective requirements. This type of labeling of the dialysis solutions or concentrates can lead to errors when providing the respective dialysis solution according to the prescription. Mistakes can occur when the user checks the labels. The user themselves can circumvent quality control via the label attached to the container by filling previously used, empty containers with concentrates of a different composition. When the concentrates are provided via a central supply line, the user cannot check the containers themselves. The lines can be mixed up, leading to errors in the composition of the flushing solution for the respective patient.The object of the invention is to provide compositions, devices, and methods which, when using dialysis compositions, enable identification of the composition by providing the information for quality assurance through coding means as components of the composition itself, i.e., the dialysis solution or concentrate. This can also be associated with a controlled activation of methods for dialysis treatment. Summary of the Invention According to the teaching of the present invention, this object is achieved by a composition according to claim 1, a sensor unit according to claim 6, and a method according to claim 15. Particular embodiments are the subject of the dependent claims. The invention relates to a composition comprising a salt mixture for producing a physiological dialysis solution.This composition can be a dry salt mixture from which a dialysis solution can be prepared by dissolving it in ultrapure water, or a liquid concentrate from which a dialysis solution can be produced by further dilution with ultrapure water. The composition can also be a liquid concentrate for preparing a dialysis solution or a ready-to-use dialysis solution, e.g., for peritoneal dialysis. Coding in the concentrate is particularly advantageous over coding in a ready-to-use solution because typical dialysis concentrates are diluted 1:34 to 1:44 before use. This allows for relatively high concentrations of coding agent for detection, since its concentration is later reduced by the dilution factor in the ready-to-use dialysis solution that comes into contact with the patient's blood.Dialysis solutions typically contain sodium, potassium, calcium, magnesium, chloride, acetate, citrate, and bicarbonate as electrolytes, and often also glucose. The composition according to the invention additionally contains a coding agent. This coding agent is a substance that differs from the standard components of a dialysis solution. By identifying the coding agent, a specification of the composition can be identified. The specification can be the concentration of ingredients. Depending on the patient's needs, dialysis solutions with different electrolyte concentrations are offered. In particular, the concentration of calcium, magnesium, potassium, or even glucose can be varied. The type of coding agent can indicate which specific composition, or in other words which type of concentrate, is involved.The specification can also represent the manufacturer's identity, batch number, or expiration date. The coding can also represent a "watermark" or "fingerprint" of the manufacturer. A type of "2-factor authentication" is also possible by combining coding on the container (e.g., QR code, RFID tag) with coding in the concentrate: Specific batch numbers are internally assigned to specific codes in the concentrate that are known only to the manufacturer. In principle, the coding agent can provide information corresponding to a label. This intrinsic label can be read automatically and is difficult to tamper with. The coding is based on the addition of a coding agent to a salt mixture to produce a dialysis solution. The coding agent can be a specific chemical substance that is not present in a standard dialysis solution.The coding agent can comprise the specific substance and its concentration. The coding agent can also comprise multiple substances and their concentration ratios to one another. Substances suitable for use as coding agents can be polynucleotides, polypeptides, urea (e.g., 1–40 mmol / L), uric acid (e.g., 0.1–4 mmol / L), ethanol (e.g., 1–100 mmol / L), creatinine (e.g., 0.1–10 mg / dL), amino acids (e.g., 0.1–50 g / L), phosphate (e.g., 0.1–10 mg / dL), zinc, or selenium. To increase measurement accuracy, the composition can also contain a standardization component in addition to the coding agent. The invention further relates to a sensor unit for coding a specification of a composition, which has at least one connection point and at least one outlet for the composition, which can be fluidically connected via a connecting line.The sensor unit has one or more sensors for determining a coding agent and a control unit configured to receive the sensor result and to convert the sensor result according to an assignment into a code that corresponds to at least one specification of the composition. The composition is an aqueous solution of a salt mixture for producing a physiological dialysis solution and at least one coding agent. The specification can be the concentration of ingredients. The specification can also represent the manufacturer's identity, batch number, or expiration date. The sensor unit can be designed such that a sensor is assigned to each connection point and the sensor is arranged in the connecting line between the connection point and the outlet. The sensor unit can also be designed such that one sensor is assigned to multiple connection points.The sensor can then be arranged in a bypass line into which the combination of several connecting lines can be fed. In the sensor unit, the connecting lines from several connection points can also be combined into a common connecting line section, and the sensor can be arranged in this common connecting line section, which is then connected to an output. The sensor can be designed to determine the chemical composition or type of the coding agent. The sensor can also be designed to determine the concentration of the coding agent(s). The sensor can be a device for determining the sequence of a polynucleotide. The sensor can be a UV or IR sensor, designed to detect the concentration of the coding agent by measuring the spectral absorption in the visible, UV, or IR range.The sensor can also be designed to perform Raman or fluorescence spectroscopy or atomic absorption spectroscopy. The sensor can be designed to use immunological detection methods. A sensor can be designed to perform various methods. This can be implemented in a miniaturized form using lab-on-a-chip technology, for example. The sensor unit can comprise a memory unit in which the assignment of the sensor results to the corresponding specifications is stored and made available to the control unit. The control unit can also receive this assignment from an external storage unit, wirelessly or via a wired connection. The sensor unit can be provided as a separate device. The sensor unit can be integrated into a central supply device. The sensor unit can be integrated into a mixing unit for producing a dialysis solution.The sensor unit can be integrated into a dialysis treatment machine. The dialysis treatment machine can enable certain dialysis treatment procedures based on the specifications determined by the sensor unit.The invention also relates to a method for determining a concentrate specification by using a composition comprising a salt mixture for producing a physiological dialysis solution and at least one coding means for coding at least one specification of this composition and a sensor unit for decoding a specification of a composition comprising at least one connection point and at least one outlet for the composition, which are fluidically connectable via at least one connecting line and a sensor for determining a coding means and a control unit configured to receive the sensor result and to convert the sensor result according to an assignment into a code which corresponds to at least one specification of the composition.Brief description of the drawings Figure 1: Device for HD, HF or HDF treatment Figure 2: Device for PD treatment Figure 3: First embodiment for a sensor unit Figure 4: Second embodiment for a sensor unit Figure 5: Third embodiment for a sensor unit Figure 6: Mixing device with integrated sensor unit Figure 7: Treatment machine with integrated sensor unit Figure 8: Use of sensor unit for diagnostic purposes. Detailed description of an embodiment The typical components of dialysis solutions are usually present in the following concentration ranges: NaCl: 110-170 mmol / l KCl: 0.7-4.3 mmol / l CaCl2: 0.7-2.0 mmol / l MgCl2: 0.3-1.2 mmol / l Glucose: 0.8-2.2 g / l Citric acid: 0.1-20 mmol / or acetate: 2-15 mmol / l Different concentrate types are then offered in this range, as shown in Table 1, for example. Table 1 Substances that differ from the standard components listed above are used as coding agents. Coding is achieved through targeted selection of the substances and / or their concentration or concentration ratio. Substances that are therapeutically safe are used here. However, the substances can also be substances that are expected to have a positive effect on the patient but are not present in standard solutions. If a special substance is used for coding, various options are available. These include short-chain polypeptides or polynucleotides that are broken down in the body. Substances that are present in the patient's blood anyway and are typically removed during dialysis are also conceivable. Their presence in the dialysis solution then only results in a slightly reduced cleaning performance due to the reduced concentration gradient.On the other hand, this reduction in purification performance may even be desirable: Excessively rapid removal can lead to what is known as disequilibrium syndrome. In this context, the addition of urea or ethanol to the dialysis solution is already used clinically. Also, for example, in long-term dialysis, the removal of certain substances that are important for human physiology can be excessive, particularly phosphate and amino acids. Therefore, the addition of phosphate and amino acids to the dialysis solution has already been clinically tested. The addition of trace elements such as zinc and selenium is also known. Therefore, concentration-based coding of concentrates containing the aforementioned substances, which are then used at the therapeutically effective concentration or a concentration below it, is readily possible. Substances that require dialysis, such as uric acid and creatinine, can also be used.Polynucleotides are coding agents that allow particularly specific information to be encoded depending on the type of substance. Similar to the natural information coding in DNA and RNA as sequences of nucleic acids, the coding of these molecules can be achieved by synthesizing molecular chains consisting of only two or a few elementary building blocks (e.g., nucleotides). With k elementary building blocks, a chain of N elements results in k. N Different combinations are possible if a "reading direction" of the chain can be identified by different ends of the chains (e.g., amino group vs. carboxyl group). Without a direction indicator (i.e., as a "palindrome"), the number of codable combinations is k N / 2. When N=10 building blocks from k=2 different types are linked together, 1024 combinations are possible; with k=4, more than a million combinations are possible. This method allows virtually any batch number to be molecularly coded. Decoding is then carried out using a suitable process when the concentrate is used. Example: The natural nucleotides adenine and thymine are used for coding. This essentially creates a binary system by assigning adenine (A) = 0 and thymine (T) = 1. A molecular chain of 8 elements would then correspond to exactly one byte (= 8 bits) of information. Appending a checksum to the code would also be possible, as is known from computer science. This would then make it possible to detect falsifications of the coding, e.g., due to chemical degradation. The decimal number 123 (binary: 01111011) would be chemically coded as follows, starting with the "lowest" bit: TTATTTTA.A "parity bit" (=1 nucleotide) or two or more nucleotides could then be added as a checksum. Using four different nucleotides (e.g., adding guanine = 2 and cytosine = 3), the same information could then be encoded at half the chain length. Encoding is also possible using different concentrations of one or more marker substances. For example, each of the k marker substances can correspond to a position in a base-N number system, where N is the number of concentration levels used. ^,^ , … , ^ ^,^ ^ Here, the concentration levels ^ ^,^be the same for all k substances. However, it can also be advantageous for later detection to use different substance-specific concentration levels. The concentration levels can be equidistant (e.g. increase of 1 mmol / L per concentration level), logarithmic (e.g. doubling from one level to the next), or freely defined. Example: The substances urea and uric acid are used for coding (=> k=2), with the urea concentration representing the lowest position and the uric acid concentration the highest position. With logarithmic coding, substance-specific N=5 concentration levels are defined: Urea: 0 -> 1 mmol / L; 1 -> 2 mmol / L; 2 -> 4 mmol / L; 3 -> 8 mmol / L; 4 -> 16 mmol / L Uric acid: 0 -> 0.1 mmol / L; 1 -> 0.2 mmol / L; 2 -> 0.4 mmol / L; 3 -> 0.8 mmol / L; 4 -> 1.6 mmol / L. This allows 52 = 25 numerical values ​​to be coded. It is also advantageous to use an additional substance as an internal standard of known concentration. For example,Ethanol could be present at a known concentration of 4 mmol / L. The concentrations of urea and uric acid can then be normalized to the ethanol concentration so that, for example, dilutions of the sample can be detected. The coding can directly contain batch numbers or concentrate types. The coding can also represent a kind of "watermark" or "fingerprint" of the manufacturer. A type of "2-factor authentication" is also possible by combining coding on the container (e.g. QR code, RFID tag) with coding in the concentrate: Certain batch numbers are internally assigned specific codes in the concentrate that are known only to the manufacturer. The compositions or dialysis solutions described above are used in renal replacement therapy. Figure 1 shows the basic structure for HD, HF or HDF treatment.Blood is withdrawn from a patient's (30) arterial vascular access (31a) by means of a blood pump (32) and fed to the dialyzer (34) via a blood tube (33a). After flowing through the dialyzer, where the blood comes into contact with the dialysis solution prepared by the dialysis machine (20) via the dialyzer membrane and supplied via the dialysis inlet (35a), thereby being freed of toxins, the blood is returned via the venous branch of the extracorporeal tubing system via the venous vascular access (31b). On the dialysate side, the dialysis solution flows downstream (35b) of the dialyzer back to the dialysis machine. The dialysis machine has all the necessary means for carrying out the various procedures such as HD, HF, and HDF, as well as means for controlled fluid removal (ultrafiltration).The display and control unit (21) is capable of receiving and processing sensor signals from the dialysis machine, as well as controlling the various actuators of the dialysis machine. Furthermore, external data such as sensor values ​​and prescriptions can be received via the communication interface 22. Values ​​determined by the dialysis machine can also be forwarded to external receivers such as computers, servers, or other dialysis machines via this interface. Figure 2 shows the typical setup for a PD treatment. Dialysis fluid in a composition typical for PD can be supplied to the patient (30) via a catheter access (41) in the peritoneum via a line (42) from the dialysis machine (40). This fluid is drained via the same connection.As with the HD device (20), the PD device comprises the display and control unit (21), which is capable of receiving and processing sensor signals from the dialysis machine and controlling the various actuators of the dialysis machine. Furthermore, external data such as sensor values ​​and prescriptions can be received via the communication interface 22. The sensor unit 1a shown in Figure 3 comprises concentrate inlets (2) with connection means and, if necessary, withdrawal means for withdrawing one to N different dialysis concentrates from storage containers. The storage containers can be smaller canisters or bags, but also larger tanks when used as a central concentrate supply. Valves (3) can be used to regulate the connection to each concentrate source Cj. In this embodiment, each concentrate line is assigned a fixed sensor Sj (5), with which an analysis can be carried out according to the type of coding means.The sensors can each be capable of carrying out one or more of the described analysis methods. The evaluation and control unit (6) receives the sensor values ​​and converts them into a numerical code according to a predetermined algorithm or a conversion table. This code, together with the assignment to the corresponding concentrate source, is then made available for further processing via the data connection (7), which can be wired or wireless. After flowing through the sensors, the concentrates are passed on via the concentrate outlets (4a) for use in the mixing units, which can be integrated into a treatment machine, for example. The evaluation and control unit (6) also receives requests for valve switching via the data connection (7).The sensor unit (1b) shown in Figure 4 has only one sensor, which is connected via bypass lines to the connecting lines between the concentrate inlets (2) with connecting means and the concentrate outlets (4a). Using suitable valve circuits, concentrates from multiple connecting lines can be analyzed with just one sensor. This can both save costs and improve comparability of the values ​​for the different concentrates. The concentrates are measured one after the other by diverting the flow of the concentrate to be measured through the sensor and then returning it to the original lines. The time of measurement and the selection of the concentrate to be measured are determined by the evaluation and control unit (6), if necessary upon external request via the data connection (7). The devices in Figures 3 and 4 allow the simultaneous use of multiple concentrates.In the device shown in Figure 5, all concentrate supply lines are combined into a single outflowing concentrate line, which then contains the sensor (5), which is then connected to a single concentrate outlet (4b). The concentrate is selected and analyzed by means of a corresponding valve circuit. The selection is again specified by the evaluation and control unit (6) following an external request via the data connection (7). The sensor unit can be provided as a separate unit. In this case, the connection means (2) can be connected to the concentrate source, e.g., to concentrate receptacles such as bags or containers. Another option is to introduce the concentrate from the outlets of a central concentrate supply. The sensor unit then acts as the central sensor and determines the coding of each individual concentrate line. Any of the embodiments shown in Figures 3 to 5 is suitable for this purpose.The concentrate outlets can then be connected to a mixing device that produces a homogenously mixed dialysis solution from ultrapure water and concentrate, which is then made available to the treatment machine. The concentrate outlets can also be directly connected to several treatment machines with an integrated mixing unit. This has the advantage that only one sensor unit is required for several machines. The coding can then be transmitted to the mixing devices or treatment machines that are supplied with the concentrates. The sensor unit can also be integrated into devices in which the concentrates are further processed. This could, for example, be in a mixing device that centrally provides the dialysis solution for several treatment machines. The sensor unit is then inserted into the internal feed line for the concentrates in the mixing device.Figure 6 shows embodiments of the mixing device (100a) using the sensor units 1a / 1b. The mixing device (100a) is fed from an ultrapure water line (101) and from the outflowing concentrate lines of the sensor units 1a / 1b. It is designed with suitable mixing means (103) such that a homogeneously mixed dialysis solution can be withdrawn from the outflow (102). In particular, it comprises controllable pumps and / or valves with which the mixing ratio can be regulated with sufficient precision. Analogously, sensor units according to Figures 4 and 5 can also be integrated into the mixing device. Another option is the integration of the sensor unit into the treatment machine. Figure 7 shows an HD device (20a) with integrated sensors and a mixing unit (100a) for the use of coded concentrates. The concentrate supply can come from alternating canisters or bags or from a central concentrate supply.Even changes in the assignment of the lines of the central concentrate supply are not a problem here. In particular, even swapping the connections of several central concentrate supplies can be detected if the concentrates contain different internal codes. Mixing takes place in the device itself. The evaluation and control unit (21) receives the code of the previously selected concentrate from the mixing unit contained in the device. If the complete concentrate type is included in the code, the evaluation and control unit (21) can immediately check whether it corresponds to the prescription that was entered on the device or received via the data connection (22). With complete coding and with coding as a "watermark", a decision can now be made automatically according to predefined rules as to whether certain treatment procedures can be carried out.In particular, certain controls or profiling of electrolyte concentrations, such as sodium, bicarbonate or potassium, can only be carried out if a recognized coding ensures that the concentrates meet the quality requirements. This can be particularly important for vulnerable patients who react with intradialytic symptoms if deviations from the ideal values ​​occur. During production of the concentrates, coding is carried out using one of the described processes by adding the substances containing the coding information to the concentrates in the defined composition. When the concentrates are used, information on the type of coding and its assignment to the concentrate types and, if applicable, batch numbers must be available on site. This can be done, for example, by transmission from a central database.When a concentrate is connected, the coding substance is sequenced using sensors or the coding is determined from the concentrations of the substances used for coding. The type of concentrate used is then directly determined from the code determined in this way. This information can then be compared with the prescription. If the coding is used as a "watermark" or "fingerprint", certain treatment procedures can be activated. It is also possible to compare it with information available on the canister or central control unit. Decoding can be done centrally or individually on the treatment device. The use of substances that require dialysis for coding can be particularly advantageous, as the sensors required for decoding can then be used simultaneously to measure the degree of blood purification.Figure 8 shows the relevant components: In a mixing unit (111), concentrate from the concentrate line (110) and ultrapure water (101) are mixed. Instead of just one concentrate line, supply from multiple lines is also possible. In particular, the mixing unit (111) comprises controllable pumps and / or valves with which the mixing ratio can be regulated with sufficient precision. The ready-mixed dialysis solution is fed to the dialyzer (34) on the dialysate side via line (35a). Downstream on line (35b) is the sensor (5). This sensor is capable of measuring the concentration of one or more substances requiring dialysis, from which conclusions can be drawn about the course of treatment. As in the embodiments shown in Figures 3 to 5, this sensor (5) is connected to an evaluation and control unit, which converts the sensor's measured value into a code, which is then made available to the treatment device via the data connection (7).In particular, this substance can be urea, uric acid, or creatinine. Typically, the measuring range of such a sensor covers approximately two orders of magnitude, although it should be noted that the dialysate concentration is usually lower than the blood concentration. By appropriately switching the valve, it is now possible to pass the concentrate, before mixing in the mixing device, directly through the sensor for measurement, instead of the outflowing dialysis solution. This typically occurs before the start of dialysis, but can also take place during dialysis. This arrangement clearly demonstrates that the substances used for coding do not impair the progress of blood purification, and secondly, the sensor is already well adapted to the coding described above.The concentration of the marker substance must be within the measuring range of the sensor, i.e., within the concentration range in which the concentration of the substances requiring dialysis lies in the effluent dialysis solution. Due to the typical measuring range of the sensor, various values ​​can be coded even with logarithmic coding, and significantly more with linear coding. Since dilution in the mixer typically occurs at a ratio of 1:34 to 1:44, the fresh dialysis solution only contains a concentration of substances requiring dialysis that is lower by this factor than the typical concentration in the effluent dialysis solution. This means that the supply of these substances to the patient via the dialyzer is negligible. The use of coded concentrates has several advantages. Identification of the concentrate type directly from the liquid or powder without the need for a container label.This is particularly advantageous if the substances used for coding are easier to detect than the therapeutically important components. The dialysis machine can then directly set the appropriate mixing ratio to produce the application concentration or prevent use after notifying the user. Quality assurance is achieved by comparing the internal coding with user inputs or information from the label (QR code, RFID, etc.). In the event of discrepancies, the user is notified and use is prevented. Certain dialysis procedures are only activated if the use of a concentrate approved by the device manufacturer is successfully detected. This includes control procedures in which the patient's physiology is to be positively influenced by the targeted adjustment of substance concentrations in the dialysate. Examples are the control of sodium, potassium and bicarbonate concentrations.

Claims

Patent claims 1. A composition comprising a salt mixture for preparing a physiological dialysis solution and at least one coding agent for coding at least one specification of this composition.

2. The composition according to claim 1, wherein the composition is a dry or liquid concentrate for a dialysis solution.

3. The composition according to any one of the preceding claims, wherein the specification or specifications are selected from the group consisting of concentrations of ingredients, manufacturer's identity, batch number, and expiration date.

4. The composition according to any one of the preceding claims, wherein the coding is based on the chemical composition and / or the concentration of the coding agent and / or the concentration ratio of multiple coding agents. 5.Composition according to one of the preceding claims, wherein the coding agents are selected from polypeptides, polynucleotides, urea, uric acid, creatinine, amino acids, phosphate, zinc, or selenium.

6. A sensor unit for coding a specification of a composition, comprising at least one connection point and at least one output for the composition, which are fluidically connectable via at least one connecting line, at least one sensor for determining a coding agent, and a control unit configured to receive the sensor result and to convert the sensor result according to an assignment into a code that corresponds to at least one specification of the composition.

7. A sensor unit according to claim 6, wherein valves are arranged in the connecting lines, and wherein the valves establish or interrupt the fluidic connection in the connecting line in response to a signal from the control unit. 8.Sensor unit according to one of claims 6 or 7, wherein the sensor determines the chemical composition of the coding agent.

9. Sensor unit according to one of claims 6 or 7, wherein the sensor determines the concentration of the coding agent(s).

10. Sensor unit according to one of claims 6 to 9, wherein the assignment of the sensor result to a specification is transmitted to the control unit wirelessly or via a wired connection from an external storage unit.

11. Sensor unit according to one of claims 6 to 10, wherein the sensor unit comprises a storage unit in which the assignment of the sensor results to the corresponding specifications is stored.

12. Sensor unit according to one of claims 6 to 11, wherein the sensor unit is a component of a central supply system for concentrates.

13. Sensor unit according to one of claims 6 to 11, wherein the sensor unit is a component of a mixing unit for producing the dialysis solution.

14. Sensor unit according to one of claims 6 to 11, wherein the sensor unit is a component of a dialysis treatment machine.Method for determining a specification by using a composition according to one of claims 1 to 5 and coding by means of a sensor unit according to one of claims 6 to 14.

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