Analytical device and analytical method

Abstract

An apparatus for analyzing a sample, the apparatus comprising: a centrifuge rotor having an analysis site suitable for receiving a sample holder having an elongated sample chamber, the analysis site extending between an inner end at a first distance from a center of rotation of the rotor and an outer end at a second distance from the center of rotation of the rotor, the inner end being closer to the center of rotation of the rotor than the outer end; a carriage having an illumination arrangement and an image sensor; and a drive arrangement operable to drive the carriage relative to the rotor along a track, the track extending between a first position relatively closer to the center of rotation of the rotor and a second position relatively farther from the center of rotation of the rotor, the track extending over at least a portion of the radial distance between the inner end and the outer end of the analysis site, the carriage operable to illuminate a portion of the analysis site with the illumination arrangement at a plurality of positions along the track and to capture an image of at least a portion of the illuminated portion of the analysis site with the image sensor.

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for analysis, in particular for analyzing fluids such as blood that contain two or more phases that can be separated from one another by a centrifugation process. [Background technology]

[0002] Existing methods for blood analysis involve drawing a blood sample into a cuvette that contains a sample chamber. The cuvette is loaded into a centrifuge and spun rapidly to separate the various phases of the blood. Following this process, the blood in the sample chamber is illuminated and an image of the blood is captured for analysis. Summary of the Invention [Problem to be solved by the invention]

[0003] It is an object of the present invention to provide an improved method and apparatus for carrying out this type of analysis. [Means for solving the problem]

[0004] Accordingly, one aspect of the invention provides an apparatus for analyzing a sample, the apparatus comprising: a centrifuge rotor having an analysis site suitable for receiving a sample holder having an elongated sample chamber, the analysis site extending between an inner end at a first distance from a center of rotation of the rotor and an outer end at a second distance from the center of rotation of the rotor, the inner end being closer to the center of rotation of the rotor than the outer end; a carriage having an illumination arrangement and an image sensor; and a drive arrangement operable to drive the carriage relative to the rotor along a track, the track extending between a first position relatively closer to the center of rotation of the rotor and a second position relatively farther from the center of rotation of the rotor, the track extending over at least a portion of the radial distance between the inner and outer ends of the analysis site, the carriage operable to illuminate a portion of the analysis site with the illumination arrangement at a plurality of positions along the track, and to capture an image of at least a portion of the illuminated portion of the analysis site with the image sensor.

[0005] Advantageously, the lighting arrangement comprises one or more first light sources.

[0006] Preferably, the first light source is positioned closer to the rotor than the image sensor is positioned relative to the rotor.

[0007] Conveniently, the illumination arrangement comprises two or more first light sources, each of the first light sources being inclined towards a main axis of the illumination arrangement.

[0008] Advantageously, the light emitted by at least two of the first light sources is focused at a position that is on or substantially on the analysis site.

[0009] Preferably, the drive arrangement is operable to cause the carriage to stop movement of the carriage at each position as an image is taken.

[0010] Alternatively, the drive arrangement is operable to drive the carriage such that movement of the carriage does not come to a complete halt as each image is captured.

[0011] Conveniently, the illumination arrangement emits only illumination below the first wavelength threshold, or substantially only illumination below the first wavelength threshold.

[0012] Advantageously, the illumination arrangement further comprises a first filter arranged such that light emitted from at least one of the first light sources passes through the first filter before illuminating the analysis site.

[0013] Preferably, the first filter only passes, or substantially passes, light having wavelengths below a first wavelength threshold.

[0014] Conveniently, the arrangement further comprises a second filter arranged such that light impinging on the image sensor passes through the second filter.

[0015] Advantageously, the second filter passes, or substantially only passes, light having wavelengths above a second wavelength threshold.

[0016] Preferably, the second threshold is higher than the first threshold.

[0017] Conveniently, the lighting arrangement further comprises one or more secondary light sources.

[0018] Advantageously, the second light source emits illumination at a frequency or range of frequencies different to that of the one or more first light sources.

[0019] Preferably, the light emitted by the one or more second light sources has a wavelength above a second threshold.

[0020] Conveniently, two of the first light sources are arranged parallel or nearly parallel to the radius of the rotor, and two of the second light sources are arranged perpendicular or substantially perpendicular to the radius of the rotor.

[0021] Advantageously, the arrangement further comprises a cuvette adapted to be received and held in the analysis site, the cuvette having an elongated analysis chamber which is parallel or substantially parallel to the radius of the rotor when the cuvette is received and held in the analysis site.

[0022] Preferably, when the cuvette is received and held at the analysis site, the trajectory of the carriage extends across a majority of the length of the sample chamber in at least one rotational orientation of the rotor.

[0023] Conveniently, the carriage track extends over the entire or substantially the entire length of the sample chamber.

[0024] Another aspect of the invention provides a method of analysing a liquid sample comprising the steps of collecting the sample in an elongated sample chamber of a cuvette, providing an apparatus as described in any preceding claim, positioning the cuvette at an analysis site on a rotor, rotating the rotor for centrifugation, and following centrifugation of the sample, driving a carriage along a track, illuminating an area of ​​the sample chamber with an illumination arrangement at one or more positions along the track, and capturing an image of at least a portion of the illuminated area of ​​the sample chamber with an image sensor.

[0025] Advantageously, the method includes the step of capturing images at a plurality of positions along the trajectory.

[0026] Preferably, the method includes capturing images of at least 10 regions of the sample chamber, more preferably capturing images of at least 30 regions of the sample chamber, and even more preferably capturing images of at least 50 regions of the sample chamber.

[0027] Conveniently, the method further comprises the step of creating a composite image of all or part of the sample chamber, the composite image comprising a combination of at least a portion of each of the captured images. [Brief description of the drawings]

[0028] In order that the invention may be more readily understood, embodiments of the present disclosure will now be described, by way of example, with reference to the accompanying drawings, in which: [Figure 1] 1 shows a cuvette suitable for use in the present invention. [Diagram 2] 1 illustrates a centrifuge rotor suitable for use with the present invention. [Diagram 3] FIG. 2 is a cutaway view of an apparatus according to the present invention. [Figure 4] 1 shows a cross-sectional view of a carriage suitable for use in the present invention. [Diagram 5] 5 shows a further view of the carriage of FIG. 4; [Figure 6] 6 shows a cut-away version of the diagram shown in FIG. 5. [Figure 7] 1 is a graph of excitation and emission spectra. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Referring to Figure 1, there is shown a cuvette 1. The cuvette 1 has a tip 2 that can be contacted with a volume of liquid to draw a sample of the liquid into a first chamber 3. The liquid is preferably drawn into the first chamber 3 by capillary action, although this is not required. The cuvette 1 also includes a sample chamber 4 that is in communication with the first chamber 3.

[0030] The sample chamber 4 is elongated and preferably of constant or substantially constant width and thickness along its length.

[0031] At one end 5, the sample chamber 4 communicates with the first chamber 3. This communication may be direct or via one or more intermediate or transition chambers (not shown). The second end 6 of the sample chamber 4 is closed and terminates in a dead end.

[0032] The characteristics of the cuvette 1 described above are known.

[0033] Once the cuvette has been used to collect a sample of a liquid, such as blood, it can be loaded into a centrifuge. In Figure 2, the rotor 7 of the centrifuge 1 is shown. The rotor 7 is generally disc-shaped and is configured to rotate about an axis of rotation 8.

[0034] The rotor 7 includes a recess 9 in its upper side 32 which is adapted to snugly receive the cuvette 1 and hold it in place during the centrifugation process.

[0035] When the cuvette 1 is inserted into the recess 9 of the rotor 7 , the sample chamber 4 of the cuvette 1 will preferably be aligned or substantially aligned with the radius of the rotor 7 .

[0036] During the centrifugation process, the rotor 7 may be rotated at a speed of 3500 rpm for a period of, for example, 20 seconds. The rotor 7 may be driven to have ramp-up and ramp-down periods, each of which may be, for example, 30 seconds.

[0037] During the centrifugation process, the liquid sample will be driven into the sample chamber 4 .

[0038] Following centrifugation of the liquid sample, the various phases of the sample will separate, with the densest phase being at the second end 6 of the sample chamber 4 furthest from the axis of rotation 8 and the least dense phase being closest to the axis of rotation 8.

[0039] In the case of a sample consisting of whole blood, the red blood cells will accumulate near the second end 6 of the sample chamber 4 furthest from the axis of rotation 8, and the less dense plasma will settle nearest the axis of rotation 8. A relatively thin layer known as the buffy coat will exist between these two major phases.

[0040] Centrifugation of blood samples is known and will not be described in detail here.

[0041] 3 shows a schematic cross-sectional view of a region of the rotor 7 after the centrifugation process. As can be seen in FIG. 3, the cuvette 1 is received within a recess 9 of the rotor 7.

[0042] The sample chamber 4 of the cuvette 1 has a length that is approximately parallel to the radius of the rotor 7, as mentioned above. The recess 9 of the rotor 7 preferably includes an opening (not shown) or a transparent window that penetrates to the bottom side 33 of the rotor 7 and is aligned with at least the sample chamber 4 of the cuvette 1. This means that the sample chamber 4 can be viewed directly from the bottom side 33 of the rotor 7 through the opening.

[0043] The analytical arrangement is positioned to one side of the rotor 7. In the illustrated example, the analytical arrangement is positioned below the rotor 7 in the normal use orientation of the rotor 7. However, it will be appreciated that in other examples the analytical arrangement may be positioned above the rotor 7.

[0044] The analytical arrangement includes a carriage 10 which, in the example shown in Figure 3, is positioned below the rotor 7. In Figure 3, the carriage 10 is shown in a first position 14 which is generally aligned with the inner end 5 of the sample chamber 4 (i.e. the end closest to the axis of rotation 8).

[0045] In a preferred embodiment, carriage 10 comprises one or more illumination sources and one or more imaging devices, as described in more detail below, and is adapted to illuminate at least one region of sample chamber 4 and capture an image of the illuminated region.

[0046] The carriage 10 is movable relative to the rotor 7 and, in a preferred embodiment, can be driven relative to the rotor 7 from a first position, for example as shown in FIG. 3, to a second position.

[0047] In a preferred embodiment, the carriage 10 may be driven along an axis that is aligned or substantially aligned with the radius of the rotor 7, although those skilled in the art will appreciate that this is not required.

[0048] The carriage 10 may be driven through a range of positions such that, when the cuvette 1 is placed in the rotor 7, it extends from one end of the sample chamber 4 to the other end of the sample chamber 4.

[0049] As noted above, in Figure 3 the carriage 10 is shown in a first position 14 aligned or substantially aligned with the inner end 5 of the sample chamber 4. Figure 3 also shows in phantom lines a second position 11 and a third position 12 into which the carriage 10 can be driven.

[0050] 3 shows a track 15 along which carriage 10 travels. In a preferred embodiment, carriage 10 is engaged with this track 15 and may be driven along the length of track 15, for example by one or more motors (not shown). However, any other suitable method for moving carriage 10 along its trajectory may be used.

[0051] In a preferred embodiment, at the end of the centrifugation process, the carriage 10 is in the initial position 14. Immediately or shortly after the centrifugation process is completed and the rotor 7 has stopped, the carriage 10 is actuated to illuminate an area of ​​the sample chamber 4 and capture an image of that area of ​​the sample chamber 4. Once the image has been captured, the carriage 10 is driven to a second position where it again illuminates an area of ​​the sample chamber 4 and captures one or more images of that area of ​​the sample chamber 4.

[0052] This process is repeated as the carriage 10 is driven to successive new positions. Preferably, the carriage 10 is driven through a range of positions including a first position at or near one end of the sample chamber 4, a final position at or near the other end of the sample chamber 4, and a number of intermediate positions between the first and final positions.

[0053] In a preferred embodiment, the carriage 10 collects images of the sample chamber 4 at at least 10 different positions. In a further embodiment, the carriage 10 collects images of the sample chamber 4 at at least 20 different positions.

[0054] In yet another embodiment, the carriage 10 collects images of the sample chamber 4 at at least 30 different positions. In a further embodiment of the invention, the carriage 10 collects images of the sample chamber 4 at at least 50 different positions.

[0055] In further embodiments, the number of positions is not fixed, but depends on the length of liquid present in the sample chamber. In these embodiments, the carriage 10 moves along the length of the sample chamber 4 and may detect (using an image sensor, described below, or any other suitable means) that liquid is present in the area of ​​the sample chamber 4 directly opposite the carriage 10. If liquid is present in that area of ​​the sample chamber 4, the carriage 10 collects images at predetermined distance intervals, which may be, for example, 0.1 mm, 0.5 mm, 1 mm, or 2 mm. However, if there is no liquid in the area of ​​the sample chamber 4, no images are collected.

[0056] In yet another embodiment, the carriage 10 may collect only a single image. If there is a single feature of interest that can be captured within the field of view of a single image, following centrifugation of the sample, the carriage 10 may be driven to a suitable position to capture a single image of that feature. The location of the feature may be determined using an image sensor in the carriage 10 or in any other suitable manner. One example of such a feature may be the buffy coat layer of a blood sample.

[0057] In embodiments, carriage 10 may come to a complete stop to capture each image. In other embodiments, carriage 10 does not stop as each image is collected. In these embodiments, carriage 10 may move at a constant or substantially constant speed along its trajectory. Alternatively, carriage 10 may move at a relatively fast speed when moving between positions and proceed at a slower speed as each image is captured.

[0058] The initial position of the carriage 10 may be aligned or substantially aligned with the inner end 5 of the sample chamber 4, as described above, in which case the carriage 10 will be driven towards the outer end 6 as images are collected. Alternatively, the carriage 10 may be aligned or substantially aligned with the outer end 6 of the sample chamber 4 in its initial position, in which case the carriage 10 will be driven towards the inner end 5 as images are collected.

[0059] The carriage 10 may have the same initial position each time an image is collected, and it is envisioned that after a set of images has been collected, the carriage 10 will be positioned at either the inner end 5 or the outer end 6 of the sample chamber 4 and will remain in this position until the device is used again, at which point this position will become the initial position for movement of the carriage 10.

[0060] It is also envisioned that when collecting a series of images, the carriage 10 may begin at a position halfway between the inner end 5 and outer end 6 of the sample chamber 4. Those skilled in the art will readily appreciate how this may be implemented.

[0061] FIG. 4 shows a more detailed view of one embodiment of a carriage 10 suitable for use in the present invention.

[0062] One end 22 of the carriage 10 includes an illumination arrangement adapted to generate illumination in an area immediately adjacent the one end 22. In use, the one end 22 of the carriage 10 is preferably the end that will be closest to the sample chamber 4. In the illustrated embodiment, the illumination arrangement comprises two first LEDs 16.

[0063] In the illustrated embodiment, the carriage 10 has a main axis 17 that may converge exactly or substantially with a portion of the sample chamber 4 of the cuvette 1 when the carriage 10 is installed in a centrifuge and the cuvette is mounted in the centrifuge rotor 7. In this example, each of the two first LEDs 16 is mounted such that it is angled towards this main axis 17.

[0064] An LED will generally have a primary illumination direction where the most intense illumination is produced. As one moves angularly away from this primary direction, the intensity of the illumination produced by the LED decreases.

[0065] Each of the two first LEDs 16 shown in FIG. 4 is inclined toward the main axis 17 in that each first LED 16 is spaced away from the main axis 17 but the main direction of illumination of each LED 16 is angled toward the main axis 17.

[0066] 4, the two first LEDs 16 are positioned on either side, or substantially on either side, of the main axis 17 and are arranged such that their main illumination directions generally coincide at a point on the main axis 17. The main illumination directions of the two first LEDs 16 also preferably converge on the sample plane, which in this example is the surface of the sample chamber 4 facing the carriage 10.

[0067] Each of the first LEDs 16 may emit illumination at about 470 nm (ie, the emission spectrum peaks exactly or substantially at 470 nm).

[0068] In the illustrated embodiment, a first filter 18 is provided in front of each first LED 16. In this example, these first filters 18 are short-pass filters that preferentially pass light having short wavelengths (such filters are also known as "high-pass" filters, since they pass higher frequencies of light).

[0069] In the illustrated embodiment, each first filter 18 is a 500 nm shortpass filter, which generally passes wavelengths of light below 500 nm, but blocks wavelengths above 500 nm.

[0070] In discussing filters herein, one of ordinary skill in the art will appreciate that the transmission profile of a filter does not have a sharp cutoff at an exact frequency.

[0071] The first LED 16 provides illumination for the area of ​​the sample chamber 4 immediately adjacent the carriage 10. Those skilled in the art will appreciate that only one first LED may be provided for this purpose, or three or more first LEDs may be provided.

[0072] Additionally, one skilled in the art will appreciate that any suitable illumination source may be used, and that it is not necessary to use LEDs.

[0073] The carriage also includes an image sensor 19, which in the illustrated embodiment includes a CMOS sensor. However, any suitable image sensor may be used, such as a CCD. It is also envisioned that the sensor may be of a type that captures data within multiple wavelength ranges across the electromagnetic spectrum, i.e., a multi-spectral sensor. The image sensor may comprise a one-dimensional array of pixels, or a two-dimensional array of pixels.

[0074] In a preferred embodiment, the carriage 10 has an imaging aperture 34 through which light may pass to impinge on the image sensor 19. In the example shown in Figure 4, the imaging aperture 34 is positioned between the first LEDs 16. The imaging aperture 34 may be positioned such that light that impinges on the carriage 10 exactly along or substantially along the primary axis 17 passes through the imaging aperture 34.

[0075] In the embodiment shown in Figure 4, the carriage 10 has a generally elongated body 20 with an illumination arrangement including a first LED 16 disposed at a first end 22 thereof, which is shown as the top end in the orientation shown in Figure 4. A lens 21 is positioned below the illumination arrangement such that light impinging on the top end 22 of the carriage 10 and passing through an imaging aperture 34 may be focused by the lens 21 onto the image sensor 19.

[0076] An autofocus lens gear and an autofocus pinion gear are provided to position the lens 21 so that the light is accurately focused. An autofocus motor and gearbox 25 is also provided to drive the autofocus lens gear and the autofocus pinion gear, as will be appreciated by those skilled in the art.

[0077] A second filter 26 is provided such that light impinging on the image sensor 19 passes through the second filter 26. In the embodiment shown in Figure 4, the second filter 26 is positioned between the imaging aperture 34 and the lens 21.

[0078] In this embodiment, the second filter 26 is a low pass filter. In this example, the second filter 26 is a 525 nm long pass filter, i.e., a filter that preferentially passes wavelengths of light above 525 nm and blocks wavelengths of light below 525 nm.

[0079] The effects of the first filter 18 and the second filter 26 will be explained in more detail below.

[0080] Those skilled in the art will appreciate that, in use, as the carriage 10 reaches each position where an image is captured, the first LED 16 illuminates an area of ​​the sample chamber 4 proximate the carriage 10 and an image of the illuminated area is captured by the image sensor 19. Thus, the carriage 10 captures a series of images along the length of the sample chamber 4.

[0081] In a preferred embodiment, there is overlap between successive images, i.e., for each image, there is at least a portion of the sample chamber 4, the liquid sample itself, and / or the rotor 7 that appears in that image and that also appears in the next image captured. It is also contemplated that in further embodiments, some or all of the images are taken without overlap with successive images. For example, images may be collected only where features of interest are located. There may be areas of the sample chamber between the features of interest that are not included in the captured images.

[0082] In a preferred embodiment, once the sample has been centrifuged, a series of images are taken within an imaging time of less than one minute.

[0083] In a further embodiment, the imaging time is less than 30 seconds.

[0084] In general, short imaging times are preferred so that the liquid phases have as little time as possible to move out of the layered arrangement immediately following the centrifugation process.

[0085] 5 shows another view of carriage 10. In this view, many of the internal components are hidden by housing 27.

[0086] In the illustrated embodiment, the first LED 16, the first filter 18, and the imaging aperture 34 are disposed on a protrusion 28 that extends from a top surface of the housing 27. A recess 29 is formed above the protrusion 28. In a preferred embodiment, the recess 29 is generally circular. In the example shown in FIG. 5, the recess 29 has a sloped sidewall 30 that extends completely around the recess 29.

[0087] The first LEDs 16 shown in Figure 4 are positioned on either side of a side wall 30. As mentioned above, the first LEDs 16 are positioned so that they are angled towards the main axis 17 of the carriage 10. In this embodiment, this is achieved at least in part by locating the first LEDs 16 on the angled side walls 30 of the recess 29.

[0088] Also, locating the first LEDs 16 on the sloping sidewall 30 allows the first LEDs 16 to be closer to the sample in the sample chamber 4, and therefore allows the sample to be illuminated as effectively as possible by the first LEDs 16. Generally, in preferred embodiments of the invention, the first LEDs 16 are positioned closer to the sample chamber 4 than the image sensor 19 is positioned relative to the sample chamber 4.

[0089] In the example shown in FIG. 5, the first LEDs 16 are not visible as they are obscured by their respective first filters 18 .

[0090] Also shown in Figure 5 is a second LED 31, which is also positioned on the side wall 30 of the recess 29. Although only one second LED 31 is visible in the embodiment of Figure 5, there is a further second LED 31 positioned in the recess 29 on an opposite side to the second LED 31 visible in Figure 5.

[0091] In a preferred embodiment of the invention, the carriage 10 is positioned relative to the cuvette 1 such that the first LEDs 16 are substantially aligned with the sample chamber 4. In other words, the lines connecting the first LEDs 16 will be parallel or substantially parallel to the length of the sample chamber 4. This ensures that the illumination generated by the first LEDs 16 illuminates the layer of liquid in the sample chamber 4 as effectively as possible.

[0092] This is preferably the case regardless of whether a second LED 31 is also provided.

[0093] 5, the second LEDs 31 are positioned approximately perpendicular to the sample chamber 4. In other words, the line connecting the second LEDs 31 will be approximately perpendicular to the length of the sample chamber 4.

[0094] Again, in the configuration shown in FIG. 5, the second LEDs 31 are angled inwards, similar to the first LEDs 16.

[0095] When the cuvette 1 is installed in the rotor 7, the main axis 17 of the carriage 10 preferably passes through or near a central region of the sample chamber 4, i.e., a region of the sample chamber 4 that is halfway or approximately halfway between the two side edges of the sample chamber 4. The second LED 31 may be angled towards the main axis 17 such that the illumination produced by the second LED 31 converges to a point on the main axis 17 that is exactly or substantially coincident with a sample plane, which is preferably the surface of the sample chamber 4 that faces the carriage 10.

[0096] Positioning the second LED 31 substantially perpendicular to the sample chamber 4 ensures that the second LED 31 effectively illuminates the edges of the sample chamber 4. This is important so that the edges of the sample chamber 4 appear clearly and distinctly in each of the images captured by the image sensor 19. This provides two advantages. Firstly, with the edges of the sample chamber 4 appearing clearly in each image, the edges of each image can be aligned with each other so that when the images are combined the images can be scaled to ensure alignment.

[0097] Secondly, with the edges clearly appearing in each image, the width of the sample chamber 4 in the images can be unambiguously determined, thus allowing accurate correction of the absolute sizes of other features appearing in the images (since the actual width of the sample chamber 4 is known).

[0098] The imaging aperture 34, in this example, is positioned at the center of the recess 29. Light may pass through the imaging aperture 34 and impinge on the image sensor 19. The imaging aperture 34 may be precisely or substantially aligned with the central axis 17, as shown in FIG.

[0099] FIG. 6 shows a cutaway view corresponding to the view shown in FIG.

[0100] FIG. 7 shows a graph of relative intensity versus wavelength and helps to illustrate the advantages of using the first filter 18 and the second filter 26.

[0101] As mentioned above, each first filter 18 is a 500 nm short pass filter and is placed in front of a respective first LED 16. In an embodiment of the invention, the blood sample in the sample chamber 4 may be mixed with a dye, acridine orange (AO), which attaches to RNA and DNA and fluoresces when illuminated with suitable radiation. Thus, the fluorescent emission of the AO can provide an accurate measure of the RNA or DNA content.

[0102] In human blood, DNA is present in white blood cells, while red blood cells contain RNA but essentially no DNA. Thus, the location of RNA and DNA in a blood sample aids in distinguishing different phases of blood.

[0103] Figure 7 shows the AO DNA and AO RNA excitation spectra. As can be seen, the AO RNA excitation spectrum 36 is almost entirely below 500 nm. Approximately half of the AO DNA excitation spectrum 35 is also below 500 nm.

[0104] 7 also shows the AO DNA emission spectrum 37 and the AO RNA emission spectrum 38. Substantially all of the RNA emission spectrum 38 is above 525 nm, and about half of the DNA emission spectrum 37 is also above 525 nm.

[0105] The first LED 16 serves to illuminate the liquid in the sample chamber 4. The light from the first LED 16 passes through a first filter 18 such that the resulting light impinging on the sample chamber 4 is of a suitable wavelength to excite AO associated with RNA and DNA in the sample.

[0106] Providing a second filter 26, which is a low-pass filter that only passes wavelengths above 525 nm, ensures that the light reaching the image sensor 19 matches most of the RNA and DNA emission spectrum of the AO, and therefore ensures that the light emitted by the sample as a result of the excitation caused by the first LED 16 successfully reaches the image sensor 19.

[0107] This arrangement of filters 18, 26 also ensures that light that reflects or refracts directly towards the image sensor 19 from the first LED 16 will be blocked by the second filter 26 and therefore will not affect the amount of useful data in the image.

[0108] Those skilled in the art will also notice that between the thresholds of the 500 nm short-pass filter and the 525 nm long-pass filter there is a gap 33 having a width of 25 nm in the illustrated example. As mentioned above, in practice the transmission profile of the filters does not contain a sharp edge at the exact wavelength, and providing this gap 33 helps to prevent light from the first LED 16 from appearing in the image collected by the image sensor 19.

[0109] In a preferred embodiment, the light from the second LED 31 is of a wavelength that passes through the second filter 26 and is thus able to pass through the second filter 26 and impinge on the image sensor 19 so that the edges of the sample chamber 4 appear clearly in the image collected by the image sensor 19.

[0110] In one embodiment, the second LED 31 emits green light having a wavelength of about 550 nm. This light is preferably reflected directly off the edge of the sample chamber and then impinges on the image sensor 19.

[0111] Importantly, the light emitted by the second LED is outside or substantially outside the AO DNA and AO RNA excitation spectra, meaning that the light from the second LED 31 does not result in unwanted excitation of AO in the sample.

[0112] The use of AO as a dye or marker is not required and one of skill in the art will be aware of other suitable dyes that may be used to assist in imaging the sample.

[0113] In general, where a sample or phase of a sample is excited by illumination with light having a first, lower range of wavelengths and subsequently emits radiation having a second, higher range of wavelengths, an apparatus embodying the invention may have an illumination source, where illumination from the illumination source passes through a first filter before impinging on the sample, the first filter blocking light having wavelengths above a first threshold, and all or most of the second wavelength range being above the first threshold. The apparatus may also have a second filter, where the second filter is configured such that light impinging on the image sensor passes through the second filter. The second filter blocks light having wavelengths below a second threshold, and all or most of the first wavelength range being below the second threshold. In these embodiments, the second threshold is higher than the first threshold.

[0114] It is also envisioned that one or more filters may be positioned to filter the light reaching the image sensor such that only wavelengths within a certain band are allowed to pass through the filter, for example wavelengths between 525 nm and 600 nm may be passed, with longer and shorter wavelengths being blocked.

[0115] Once a series of images have been taken, they can be combined to form a single composite image, which preferably covers the entire length of the sample chamber 4 occupied by the liquid sample. The composite image can be created by matching portions of the edges of successive images, i.e., by matching features that appear in both images. This technique is well understood and will not be described in detail herein.

[0116] The generation of this single image allows for precise analysis of the phase of the sample contained in the sample chamber 4 .

[0117] For example, if the length of the sample chamber occupied by red blood cells can be accurately measured, and the total length of the sample (including all phases) can also be accurately measured, the ratio of the volume of red blood cells to the total volume of the sample can be determined. Measuring the phases in this manner can allow, for example, accurate determination of the hematocrit and / or mean corpuscular hemoglobin concentration (MCHC) of the blood sample.

[0118] The layers appearing in the buffy coat region of the sample may also be analyzed in detail.

[0119] Alternatively to this, as described above, the carriage 10 may collect images only at locations of interest. There may be areas of the sample chamber 4 that are not included in the images collected by the carriage 10.

[0120] In these embodiments, the position of carriage 10 when each image is taken may be recorded to allow for accurate determination of the position of that image. As an example of this, the number of steps of the motor driving carriage 10 may be used to determine the position of carriage 10 when the image was taken.

[0121] In some embodiments, the carriage 10 may capture images only in positions or ranges of positions where features of interest are likely to be found. For example, if it is desired to capture images of the buffy coat region of a blood sample, the carriage may capture images only in the regions where the buffy coat is likely to be. As an example, it may be expected that 30%-60% of the total volume of a blood sample will contain red blood cells. The buffy coat layer is substantially immediately adjacent to the end of the sample portion that contains red blood cells. Thus, the carriage 10 may be controlled to collect images in a region that covers a range of positions where the end of the sample portion that contains red blood cells is likely to be. This region extends to cover this range of positions and may also include a margin on either side of the range of positions. The margin may be, for example, 5% of the volume of the sample, so in this example, the carriage 10 will capture images within a range of 25%-65% of the volume of the sample (extending from the second end 6 of the sample chamber 4). There may be regions on either side of this range where no images are captured.

[0122] If a stepper motor is used, the range of positions at which images are captured can be controlled by specifying the range of motor steps at which images are captured. For example, carriage 10 can be controlled to capture images between 1,000 and 1,500 steps.

[0123] As an alternative to this, the images captured by the carriage 10 may be analyzed to determine if features of interest are present. Continuing with the buffy coat example, the buffy coat has a distinctive color that is distinct from the color of the red blood cells and plasma on either side of the buffy coat. The carriage 10 may advance along the length of the sample chamber and capture images at intervals, within a preset range or over the entire length of the sample. After each image is taken, the image may be analyzed (e.g., by analyzing the presence or intensity of one or more colors in the image, which may be accomplished by determining a profile for each color channel) to reach a determination as to whether the buffy coat or any portion of the buffy coat appears in the image. If it is determined that the buffy coat does not appear in the image, the image is discarded without being stored. However, if any portion of the buffy coat appears in the image, the image is stored (along with data representative of the position of the carriage 10).

[0124] After the carriage 10 has been driven along the length of the sample chamber 4, the relative positions of the collected images can be determined and therefore the distances between features appearing in the images can be accurately calculated. Optionally, a composite image may be created based on the collected images, the composite image having gaps corresponding to areas of the sample chamber where images were not collected.

[0125] In some embodiments, only a single image may be taken covering the feature of interest.

[0126] Taking multiple relatively close-up images of parts of a sample, rather than taking one "wide-angle" image of the sample, means that the resolution achieved can be significantly greater than traditional methods that take one wide-angle image of the entire sample. The resolution achieved using embodiments of the invention can also make it possible to distinguish between different types of blood cells. Resolutions of around 5 μm can be achieved, with the majority of white blood cells having a size in the range of 10-15 μm.

[0127] Texture analysis may also be used to distinguish between different layers or components of a sample. For example, if a first layer or region has cells about 2 μm in size and a second layer or region has cells about 15 μm in size, it may be possible to algorithmically distinguish the layers or regions due to differences in the patterns of each region of the image.

[0128] In an embodiment of the invention, each image collected by carriage 10 corresponds to a field of view of approximately 3 mm wide and approximately 2.4 mm long. Preferably, each image corresponds to a field of view of 5 mm by 5 mm or less, and more preferably, each image corresponds to a field of view of 3 mm by 3 mm or less.

[0129] In the configuration described above, the illumination arrangement and the image sensor are provided on a single carriage. However, it is envisioned that in other embodiments, the illumination arrangement may be positioned on one side of the sample chamber and the image sensor may be provided on the other side of the sample chamber. In such embodiments, a moving carriage may be provided that includes an image sensor but not an illumination arrangement. The carriage may be driven to move along all or part of the length of the sample chamber and capture images, as described above. When this occurs, the illumination arrangement will illuminate the sample from the other side of the sample chamber (e.g., the carriage may be positioned below the rotor and the illumination arrangement may be positioned above the rotor, or vice versa).

[0130] The illumination arrangement may illuminate all or substantially all of the sample in the sample chamber as each of the images is captured. In such an embodiment, the illumination arrangement may include a series of light sources, such as LEDs, that are aligned or substantially aligned with the length of the sample chamber such that the entire sample chamber is illuminated as the image is captured.

[0131] Alternatively, only the area in which an image is being captured may be illuminated by the illumination arrangement. In such an embodiment, the illumination arrangement may still include a series of light sources aligned or substantially aligned with the length of the sample chamber, but only a subset of the light sources that illuminate a region of the sample is activated when an image of that region is captured. As a further alternative, the illumination arrangement may be provided as part of a second carriage that is driven to travel along all or part of the length of the sample chamber. The second carriage may be driven to move in the same manner as the carriage containing the image sensor.

[0132] Those skilled in the art will appreciate that embodiments of the present invention provide powerful and improved devices and methods for analyzing blood samples and will find application in many fields.

[0133] As used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. These terms are not to be interpreted as excluding the presence of other features, steps or components.

[0134] The invention may also broadly reside in any and all combinations of two or more of the moieties, elements, steps, examples and / or features referred to or indicated herein, individually or collectively. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

[0135] Protection may be sought for any features disclosed in any one or more of the publications referenced herein in combination with this disclosure.

[0136] Although specific exemplary embodiments of the present invention have been described, the appended claims are not intended to be limited to only those embodiments, and the claims should be construed literally, intentionally, and / or to encompass equivalents.

Claims

1. An apparatus for analyzing a sample, wherein the apparatus is A centrifuge rotor having an analysis site suitable for receiving a sample holder having an elongated sample chamber, wherein the analysis site extends between an inner end at a first distance from the center of rotation of the rotor and an outer end at a second distance from the center of rotation of the rotor, the inner end being closer to the center of rotation of the rotor than the outer end, and the centrifuge rotor, A carriage having an illumination component and an image sensor, A drive component capable of operating to drive the carriage relative to the rotor along a track, wherein the track is It extends between a first position relatively close to the rotation center of the rotor and a second position relatively far from the rotation center of the rotor, The track comprises a drive component that extends over at least a portion of the radial distance between the inner end and the outer end of the analysis site, The apparatus is configured such that the carriage is operable to illuminate a portion of the analysis site at multiple positions along the trajectory using the lighting configuration, and is operable to capture an image of at least a portion of the illuminated portion of the analysis site using the image sensor.

2. The apparatus according to claim 1, wherein the lighting configuration comprises one or more first light sources.

3. The apparatus according to claim 2, wherein the first light source is positioned closer to the rotor than the image sensor is positioned relative to the rotor.

4. The apparatus according to claim 2, wherein the lighting configuration comprises two or more first light sources, and each of the first light sources is inclined toward the main axis of the lighting configuration.

5. The apparatus according to claim 4, wherein light emitted by at least two of the first light sources converges at a position on or substantially on the analysis site.

6. The apparatus according to claim 1, wherein the drive component is operable to stop the carriage from moving at each position when an image is captured.

7. The apparatus according to claim 1, wherein the drive component is operable to drive the carriage such that the movement of the carriage does not completely stop when each image is captured.

8. The apparatus according to claim 2, wherein the lighting configuration emits only illumination below a first wavelength threshold, or substantially only illumination below a first wavelength threshold.

9. The apparatus according to claim 8, wherein the lighting configuration further comprises a first filter, the first filter being arranged such that light emitted from at least one of the first light sources passes through the first filter before illuminating the analysis site.

10. The apparatus according to claim 9, wherein the first filter allows or substantially allows light having wavelengths below the first wavelength threshold to pass through.

11. The apparatus according to claim 8, further comprising a second filter, wherein the second filter is arranged such that light striking the image sensor passes through the second filter.

12. The apparatus according to claim 11, wherein the second filter allows or substantially allows light having wavelengths above a second wavelength threshold to pass through.

13. The apparatus according to claim 12, wherein the second threshold is higher than the first threshold.

14. The apparatus according to claim 12, wherein the lighting configuration further comprises one or more second light sources.

15. The apparatus according to claim 14, wherein the second light source emits illumination at a frequency or frequency range different from the frequency or frequency range of the one or more first light sources.

16. The apparatus according to claim 14, wherein the light emitted by one or more second light sources has a wavelength exceeding the second threshold.

17. Two first light sources are arranged so as to be parallel or substantially parallel to the radius of the rotor, The apparatus according to claim 14, wherein two of the second light sources are arranged perpendicular or substantially perpendicular to the radius of the rotor.

18. The apparatus according to claim 1, further comprising a cuvette adapted to be received and held in the analysis site, wherein the cuvette has an elongated analysis chamber, the analysis chamber being parallel or substantially parallel to the radius of the rotor when the cuvette is received and held in the analysis site.

19. The apparatus according to claim 18, wherein, when the cuvette is received and held in the analysis site, the trajectory of the carriage extends over most of the length of the sample chamber in at least one rotational direction of the rotor.

20. The apparatus according to claim 19, wherein the trajectory of the carriage extends over the entire or substantially the entire length of the sample chamber.

21. A method for analyzing a liquid sample, wherein the method is The steps include collecting the sample in the elongated sample chamber of the cuvette, The steps of providing the apparatus described in claim 1, The steps include placing the cuvette within the analysis site of the rotor, The steps include rotating the rotor to centrifuge the sample, Following the centrifugation of the sample, the steps include: driving the carriage along the trajectory; and illuminating a region of the sample chamber at one or more positions along the trajectory using the illumination component. A method comprising the step of acquiring an image of at least a portion of the illuminated area of ​​the sample chamber using the image sensor.

22. The method according to claim 21, further comprising the step of acquiring images at multiple locations along the trajectory.

23. The method according to claim 22, comprising the step of acquiring images of at least 10 regions of the sample chamber, more preferably the step of acquiring images of at least 30 regions of the sample chamber, and even more preferably the step of acquiring images of at least 50 regions of the sample chamber.

24. The method according to claim 21, further comprising the step of creating a composite image of all or part of the sample chamber, wherein the composite image includes a combination of at least a portion of each of the captured images.

Images