DE19852504A1 - Blood analysis arrangement and method for serodiagnostics - Google Patents

Abstract

The invention relates to a blood analysis device and method for establishing a serodiagnosis. The method includes performing a test and assessing results of said test in an objective and reliable manner. The inventive device comprises a sample holder (14) having at least one cavity (12) for receiving blood samples (18) and reagents; a light source (24) for illuminating the cavity (12) to be analysed; a colour image acquisition device (10) for 2D-scanning of the cavity (12) to be analysed, which is used for delivering image signals associated to a respective colour; an analog/digital converter (50) for converting image signals into digital image data associated to image points and divided into fundamental colours, in the form of image points; an image processing unit (16) for processing said image data, used for reproduction and/or classification of reaction patterns of a blood sample (18), which are formed in said cavity (12).

Description

The invention relates to an arrangement and a method for blood analysis for serodiagnostics, in particular for capturing, evaluating and reproducing image data in blood group serology.

In serodiagnostics or blood group serology for blood group determination or for in vitro slide diagnosis of infectious diseases specific to anti detection reactions based on gene-antibody reactions triggered in the sample substances and their appearance form of assessment. For example, at Hemagglutination tests over red blood cells in blood samples Membranes or other fixed antigens specifically clumped and the agglutination patterns of the precipitated complexes after one of negative (none Agglutination) up to fourfold positive (strong agglutina tion) graded grading system semi-quantitative evaluates. Alternatively, so-called solid phase Methods for the search and identification of erythrocytes antibodies as well as for cross-checking which positive reactions become more bound as a layer  Erythrocytes on specially prepared solid phases put.

In this context, it is known the test substance zen in the wells or wells of microtiter plate and the reaction pattern with the naked eye to judge visually. It is considered disadvantageous that this subjective type of determination is especially important in Transition phases can lead to misjudgments that possibly serious consequences for example provide evidence of intolerance to blood transfusions pull yourself. In addition to experience and expertise required visual observation, especially in series analyzes a lot of time. In addition, the reacti ons only in a narrowly limited time window Allow visual evaluation.

Based on this, the object of the invention reasons, an arrangement and a method for testing to indicate the evaluation in serodiagnostics, with which in economical and repeatable way preferably au Reliably determine tomatically precise test results to let.

To solve this task the in the independent gene claims 1 and 13 specified  binations suggested. Advantageous configurations and further developments of the invention result from the dependent claims.

The analysis arrangement according to the invention accordingly comprises:

• - at least one cavity for receiving blood samples as well as detection reagents preferably as a microtiter plate or microtiter streak fen trained sample carriers,
• - To examine a light source for illuminating the the cavity,
• - A color image sensor for two-dimensional scanning of the cavity to be examined and color selection ven generation of image signals,
• - An analog / digital converter to implement the picture signals assigned in pixels and pixel by pixel digital image data divided into primary colors, and
• an image processing unit processing the image data device for reproducing and / or evaluating the Image data especially for the classification of in the Cavity-trained reaction patterns of the blood sample.

This makes it possible to use a true-to-color and genuine image of the under looking for cavities at any time after de mechanically defined criteria and to do document. In particular, different colors  gradations in the reaction patterns that a mere The black and white picture may not be distinguishable would be recognized to avoid misjudgments become. The arrangement allows for rational and extremely reliable way to do blood tests.

According to a particularly advantageous embodiment of the Invention has the image processing device Video controller and a color screen unit to the front preferably enlarged color image reproduction of the image data on. It can be used in parallel or in addition to a classic one visual assessment made by a specialist be, the image with a multiple of the origi size can be displayed.

The image processing device is advantageous with a storage medium for storing the image data in association with patient data to the Document test results and follow them up at any time to make it drawable.

It is good for a high processing speed stig when the image processing device with an image processor coupled image processor.  

The required color sensitivity and resolution can be achieved in that the color image pickup by a semiconductor image sensor, in particular a CCD image sensor, in three basic colors fen working video camera is formed. It is further advantageous in terms of increasing the resolution liable if the color image pickup is one on the underneath looking cavity on focusable imaging optics points. In this context, the sample processing by a positioning device for sequential len positioning of a plurality of cavities of the Simplified sample carrier in one measuring position.

To avoid image errors, it is advantageous if the light source through a voltage-stabilized elec trical white light source and possibly one of the White light source downstream diffuser is formed. Another improvement is the color image Intermittent gray filter for intermittent the calibration of the homogeneity and intensity of the Light source achieved. It is also favorable if that Color image sensor in the ultraviolet and infrared Blocking wavelength range and in the visible range richly transparent measuring light filter is arranged.  

To simplify the automatic documentation of the Analysis data is provided that on the sample carrier patients scanned by means of the color image sensor Data are preferably applied as a bar code.

In procedural terms, the above-mentioned task is solved by the following procedural steps:

• - one for taking blood samples and test reagents trained cavity of a sample holder is in egg positioned its measuring position,
• - The cavity in the measuring position will be lights up and using a color image sensor underneath color-selective generation of analog image signals scanned two-dimensionally,
• - The image signals are assigned in pixels and Digitally divided into primary colors pixel by pixel Image data implemented,
• - The image data are processed using image processing device especially for the classification of in the reaction patterns formed in the cavity give and / or evaluated.

As an alternative or in addition to the automatic evaluation, the image data can be displayed on a display unit as a preferably enlarged color image of the detected cavity, optionally in conjunction with evaluation results. It is further provided that the image data are stored on a storage means in association with patient data
In order to enable a reaction-specific differentiation, it is proposed that the pixels are assigned a characteristic value for area segmentation of the reaction patterns in accordance with the color components of the assigned image data or a color tone derived therefrom. An objective test evaluation is achieved in that coherent pixel areas with matching characteristic values are determined, surface features of the pixel areas such as diameter, center of gravity, area content and compactness are determined, and that the reaction pattern is classified by comparing the area features with empirical default values.

Another simplification in image processing and Evaluation is achieved in that the pixels binary to generate color-specific black and white images Characteristic values can be assigned.

In an agglutination test, appear together clumped erythrocytes as dark red sediment, weh reverse in a solid phase test  Erythrocyte sediment as an expression of a negative reac tion is obtained. To make them highly sensitive It is there that these reaction characteristics are separated and separated particularly advantageous, the pixels with a uniform color in the red-black area a binary characteristic is assigned. More test tubes Relevant statements can be obtained from the fact that at a pixel agglutination or solid phase test with a hue in the yellow-brown area a binary characteristic value is assigned uniformly.

To obtain a gray scale image of the cavity to be measured with obtain clearly defined gray levels, it is advantageous if made to measure for each pixel the color components of the assigned image data or of a color tone derived from it has a gray value is communicated. A preferred evaluation option sees then before that on the total number of pixels-e standardized frequency of the individual gray values of the gray value image is determined as a gray value distribution curve, and that from the gray value distribution curve, parameters for Classification of a reaction pattern in the Kavi blood sample can be derived. This can advantageously done that from a minimum a threshold value is determined in the gray value distribution curve and that the pixels with gray values above  of the threshold, a first characteristic value and the picture score with gray values below the threshold a second characteristic for area segmentation of the Re action pattern is assigned.

A further procedural design provides that from the gray scale image for at least one linear Pixel sequence a gray value curve in dependent speed is determined from the pixel position, and that from parameters of the gray value curve by Ver a reaction with given threshold values pattern is classified.

In the following the invention is based on one in the Drawing shown in a schematic manner example explained in more detail. Show it

Fig. 1 is a block diagram of an arrangement for blood analysis in blood group serology;

Fig. 2 is a ten microwells with several Kavitä and present therein solid phase tests with differently configured reaction patterns in a broken plan view;

Fig. 3 is an enlarged view of the mean Ka vity of Figure 2 with differently shaped and color-distinguishable reaction areas.

Fig. 4 is a simplified representation of a gray scale image of an agglutination test in a Ka tivity;

FIG. 5 shows a histogram of the gray scale image according to FIG. 4;

FIG. 6 shows a gray-scale image of a cavity corresponding to FIG. 4 to illustrate a linear evaluation of the image; and

Fig. 7 shows the gray value profile of the image data along the broken scan line in FIG. 6.

The arrangement shown symbolically in FIG. 1 for serodiagnostic blood analysis enables the acquisition, storage, reproduction and evaluation of image data from blood tests on blood samples. Blood samples are considered to be samples which have at least one blood ingredient such as blood plasma, blood serum or cellular elements. The arrangement consists essentially of a color image sensor 10 for two-dimensional scanning of the sample vessels or cavities 12 of a sample carrier 14 designed as a microtiter strip or microtiter plate, and a digital image processing device 16 for determining reaction patterns of the blood samples 18 presented in the cavities 12 together with test reagents .

The sample holder 14 can be positioned in a measuring chamber 20 by means of a positioning device 22 , so that one of the cavities 12 is arranged in a measuring position. To illuminate the cavity 12 to be measured, a light source 24 is used , which is a high-frequency white light source 28 that is voltage-stabilized by means of a stabilizer circuit 26 . and a diffusion plate 30 arranged between the white light source and the cavity.

The color image sensor 10 is formed by a video camera 32 , which has a CCD image sensor 34 operating in the three basic color levels red, green, blue (R, G, B). Imaging optics 36 are arranged in front of the CCD image sensor 34 and enable the sensor surface to be focused on the facing inner wall of the cavity 12 in the measuring position. An interchangeable optics 40 which can be actuated by means of actuator 38 serves to bring various optical elements into the beam path between the cavity 12 and the color image sensor 10 . A measuring light filter 42 of the interchangeable optics 40 transmits the measuring light emanating from the cavity 12 in the visible wavelength range and blocks in the UV and IR range. A gray filter 44 enables the light source 24 to be calibrated by taking blank images, on the basis of which the homogeneity and intensity of the illumination can be checked. A concave lens 46 is provided to focus the color image pickup 10 on the surface of the sample carrier 14 in order to scan a bar code marking there for sample and sample identification.

The analog RGB image signals supplied by the color image sensor 10 can be converted in an analog / digital converter 50 into image data or pixels associated with digital image data. The detected cavity 12 is mapped onto a two-dimensional pixel matrix, three image data being assigned to each pixel as RGB values. Alternatively, these RGB values can be converted into a so-called HSI color model, in which there are pixel-divided values for the hue (H), the saturation (S) and the brightness (I). This digital image data can be further processed in an image processor 52 coupled to a RAM image memory and optionally displayed on a monitor 56 as a faithful, preferably enlarged color image via a video controller 54 or on a permanent memory 58 in association with patient data, preferably in a database format lay down.

Fig. 2 shows a microtiter strip 14 , which is coated on the walls 60 of its cavities 12 with a reactive solid phase layer of immobilized erythrocytes with selected antigenic patterns. Antibodies from sera or plasmas can be bound to these erythrocytes. An erythrocyte double layer or a cell lawn 62 is formed if sufficient amounts of erythrocytic antibodies are present in the sample to be examined. Correspondingly, a quadruple positive reaction is shown in the left cavity in FIG. 2, while a weaker positive reaction pattern (++) is shown in the middle cavity. Negative results (-) can be seen on buttons of unbound cells which collect by centrifugation as erythrocyte sediment 64 in the center of a cavity 12 ( FIG. 2, right).

The reaction patterns can be based on the obtained Computationally image data with different methods  analyze. An overall result from the Re results of the individual methods, whereby their un various restrictions and inaccuracies if necessary by a corresponding mathematical Ge weighting can be taken into account.

A first evaluation method is in the picture use color information directly from data, about evaluation characteristics from test-specific areas to be able to extract the reaction pattern. Doing so first to segment the reaction pattern in related areas according to the pixels the color components of the assigned image data or one a characteristic value is assigned to the color tone derived therefrom. For the pixel areas with matching characteristics surface features such as diameter, Determine center of gravity, area and compactness, based on which the reaction pattern in the cavity Comparison with empirically determined default values is sified.

To simplify the evaluation, color-specific black and white images can be generated by assigning binary parameters. Thus, a first black and white image in which solid-phase reac tion pattern of FIG. 3 as obtained by that the pixels of the cell sheet 62 color lying due to their brown yellow in the range tons a characteristic value "black" and the remaining pixels of a characteristic value "white" is allocated. Correspondingly, the sediment area 64 , the pixels of which have a hue lying in the red-black area, is shown separately as a second black and white image data set. Then, based on the average size of the black area in the first image and at the same time a pronounced black area in the second image, a double positive reaction (++) can be concluded.

Further evaluation methods are based on an indirect one Gray value analysis of the reaction patterns. To this Purpose is from the color portions of the image data or de hue a gray value to produce a gray value image determined. An extensive evaluation then provides that the total number of the picture points standardized frequency of the individual gray values as Gray value distribution curve is determined, and that extreme values and integral values of curve sections to class sification of a reaction pattern can be determined.

As an example of this method, a simplified gray-scale image of an agglutination test is shown in FIG. 4, in which erythrocytes adhered to one another have formed a compact agglutinate 66 . The dashed boundary line 68 encloses an evaluation area whose gray value distribution is shown as a gray value distribution curve or histogram 70 in FIG. 5. The curve 70 has two clearly distinguishable peak areas 72 , 74 , which are separated by a local minimum at gray value 45 , the area 72 being assigned to the light image background and the area 74 to the dark cell clumps. The calculation of the cumulative frequency or the curve integral below the single minimum found enables an empirical classification of the reaction picture into a 4- fold positive in the given case.

In general, various characteristics of curve 70 can be used for classification, in particular the number of local minima, the number of iterative search steps until a minimum is first found, the cumulative frequencies below a first and possibly a second minimum, and the cumulative frequency in an area around the absolute maximum, the latter as a measure of the uniformity of the background. Alternatively, an area segmentation analogous to the color evaluation described above is also conceivable, a threshold value being determined from a minimum of the gray value distribution curve and a first characteristic value being assigned to the pixels with gray values above the threshold value and a second characteristic value being assigned to the pixels with gray values below the threshold value.

A further evaluation or classification option results from a line-related analysis of the gray value image. In this case, for at least one linear pixel sequence or scan line 76 ( FIG. 6), a gray value curve 78 is generated from the gray value image, as is shown in FIG. 7 as a function of the pixel position. Characteristics of curve 78 are determined as evaluation criteria. In a first step, the maximum and minimum gray values are determined and a percentage discount or surcharge is added. The intersection points 80 , 80 ', 82 , 82 ' with the curve 78 are searched for the resulting gray value levels. The gradients GRAD at points 80 , 82 and 80 ', 82 ' and the intersection of the straight lines defined by these pairs of points are then calculated as parameters. Further parameters result from the contrast difference DIFF between points 80 , 82 and 80 ', 82 ' and the diameter DIAM between points 82 , 82 '. In addition, the continuity and the variance of the gray values as a measure of the homogeneity of the image content are checked in sections. The results are assigned by comparing the parameters obtained with empirical threshold values. A strongly positive reaction requires, for example, a diameter DIAM greater than 100 pixels, a contrast difference DIFF of more than 25 and a gradient GRAD of more than 45 °.

Claims (24)

1. Arrangement for blood analysis for serodiagnostics with

• a) an at least one cavity ( 12 ) for receiving blood samples ( 18 ) and detection reagents, preferably designed as a micro titer plate or microtiter strip, sample carrier ( 14 ),
• b) a light source ( 24 ) for illuminating the cavity ( 12 ) to be examined,
• c) a color image sensor ( 10 ) for two-dimensional scanning of the cavity to be examined ( 12 ) and color-selective generation of image signals,
• d) an analog / digital converter ( 50 ) for converting the image signals into pixels assigned and pixel-wise divided into primary colors digital image data,
• e) an image processing unit processing the image data ( 16 ) for reproducing and / or evaluating the image data, in particular for classifying reaction patterns of the blood sample ( 18 ) formed in the cavity ( 12 ).

2. Arrangement according to claim 1, characterized in that the image processing device ( 16 ) has a video controller ( 54 ) and a color display unit ( 56 ) for preferably enlarged color image reproduction of the image data. 3. Arrangement according to claim 1 or 2, characterized in that the image processing device ( 16 ) has a storage medium ( 58 ) for storing the image data in association with patient data. 4. Arrangement according to one of claims 1 to 3, characterized in that the image processing device ( 16 ) has a ge coupled to an image memory image processor ( 52 ). 5. Arrangement according to one of claims 1 to 4, characterized in that the color image sensor ( 10 ) is formed by a semiconductor image sensor ( 34 ), in particular a CCD image sensor having video camera ( 32 ) working in three basic color levels. 6. Arrangement according to one of claims 1 to 5, characterized in that the color image sensor ( 10 ) has an imaging lens ( 36 ) which can be focused on the cavity ( 12 ) to be examined. 7. Arrangement according to one of claims 1 to 6, characterized by a positioning device ( 22 ) for the sequential positioning of a plurality of cavities ( 12 ) of the sample carrier ( 14 ) in a measuring position. 8. Arrangement according to one of claims 1 to 7, characterized in that the light source ( 24 ) by a voltage-stabilized electrical white light source ( 28 ) and optionally one of the white light source downstream diffuser ( 30 ) is ge. 9. Arrangement according to one of claims 1 to 8, characterized by a gray color filter ( 44 ) connected upstream of the color image sensor ( 10 ) for intermittently calibrating the homogeneity and intensity of the light source ( 24 ). 10. Arrangement according to one of claims 1 to 9, characterized by a the color image sensor ( 10 ) upstream, blocking in the ultraviolet and infrared wavelength range and transparent in the visible measuring light filter ( 42 ). 11. Arrangement according to one of claims 1 to 10, characterized in that abtastba re patient data ( 48 ) are preferably applied as a bar code on the sample carrier ( 14 ) by means of the color image sensor ( 10 ). 12. Arrangement according to one of claims 1 to 11, characterized by by means of the image processing device ( 16 ) controllable interchangeable optics ( 38 , 40 ) for optional positioning of filters or imaging lenses in front of the color image sensor ( 10 ). 13. Method for blood analysis for serodiagnostics in which

• a is positioned) an opening formed for receiving blood (18) and test reagents cavity (12) ei nes sample carrier (14) in a measuring position,
• b) the cavity ( 12 ) located in the measuring position is illuminated and scanned two-dimensionally by means of a color image sensor ( 10 ) with color-selective generation of analog image signals,
• c) the image signals are converted into digital image data assigned to pixels and divided into primary colors pixel by pixel,
• d) the image data, in particular for the classification of reaction patterns formed in the cavity ( 12 ), are reproduced and / or evaluated by means of an image processing device ( 16 ).

14. The method according to claim 13, characterized in that the image data on a color screen unit ( 56 ) as a preferably enlarged color image of the detected cavity ( 12 ) are optionally displayed in conjunction with evaluation results. 15. The method according to claim 13 or 14, characterized in that the image data are stored on a non-volatile storage means ( 58 ) in association with patient data. 16. The method according to any one of claims 13 to 15, there characterized by that according to the pixels Specification of the color components of the assigned image data or a color tone derived therefrom a characteristic value for area segmentation of the reaction patterns is assigned. 17. The method according to claim 16, characterized in that contiguous pixel areas ( 62 , 64 ) are determined with matching parameters, that area features of the pixel areas ( 62 , 64 ) such as diameter, center of gravity, area content and compactness are determined, and that the reaction pattern is classified by comparing the area characteristics with empirical default values. 18. The method according to claim 16 or 17, characterized ge indicates that the pixels for generation color-specific black and white images binary characteristics  can be assigned. 19. The method according to any one of claims 16 to 18, there characterized in that at an agglutina tion or solid phase test the pixels with egg color in the red-black area a binary characteristic value is assigned uniformly. 20. The method according to any one of claims 16 to 19, there characterized in that at an agglutina tion or solid phase test the pixels with egg color in the yellow-brown area a binary characteristic value is assigned. 21. The method according to any one of claims 13 to 15, characterized in that a gray value for determining a gray value image ( 66 ) of the cavity to be measured ( 12 ) is determined for each pixel in accordance with the color components of the associated image data or a color tone derived therefrom . 22. The method according to claim 21, characterized net gekennzeich that normalized to the total number of pixels frequency of the individual gray-scale values is determined the gray value image as a gray-scale value distribution curve (70), and that from the Grauwertvertei distribution curve (70) parameters for classification ei nes reaction pattern of the in the cavity ( 12 ) be derived blood sample. 23. The method according to claim 22, characterized in that a threshold value is determined from a minimum of the gray value distribution curve ( 70 ), and that the pixels with gray values above the threshold value have a first characteristic value and the pixels with gray values below the threshold value have a second characteristic value is assigned to the segmentation of the reaction pattern. 24. The method according to claim 21, characterized in that a gray value curve ( 78 ) is determined as a function of the pixel position from the gray value image ( 66 ) for at least one linear pixel sequence ( 76 ), and that from parameters of the gray value curve ( 78 ) a reaction pattern is classified by comparison with predetermined threshold values.