Appliance and method for evaluation and assessment of a test strip

• US 8,848,988 B2
• Filed: 11/16/2009
• Issued: 09/30/2014
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: Chembio Diagnostics Holdings Germany GmbH (Chembio Diagnostics, Inc.)
• Original Assignee: OpTricon GmbH
• Inventors: Plickert, Volker, Melchior, Lutz, Hein, Wilko, Jdicke, Thorsten
• Primary Examiner(s): Carter, Aaron W
• Application Number:
  US13/129,508
• Publication Number:
  US 20110293153A1
• Time in Patent Office: 1,779 Days
• Field of Search: 382/128, 382/133, 382/134
• US Class Current: 382/128
• CPC Class Codes: G01N 21/8483 Investigating reagent band test-element handling not specific to a test method G01N33/4875; analytical elements specific to chemical analysis of biological material G01N33/52; autometer with reagent band G01N35/04

Abstract

The invention relates to a method for quantitative determination of test results from diagnosis methods with the aid of an optoelectronic evaluation appliance, and to the evaluation appliance itself, characterized in that the digital pixel information per color level or grey level is represented in its intensity in the microprocessor as one column per pixel, wherein the column height corresponds to the intensity, and these columns are displayed alongside one another on one plane, such that the intensity distribution is displayed over the test area as a surface contour or surface profile, the height profile of which corresponds to the intensity profile of the color intensity received by the CCD. Fields of application for the invention are test methods in biochemical laboratories, such as medical diagnosis, forensic medicine, foodstuff diagnosis, molecular biology, biochemistry, gene technology and all other related fields, as well as patient monitoring for home users or in pharmacies.

Claims

1. Method for evaluation of a test strip with an appliance containing an insert, an optic portraying the image of the test strip onto a receiver, reference fields or reference images, as the case may be, a reception component, lighting for the test strip, evaluation electronics containing an evaluation algorithm, a display, an energy supply and electrical interfaces as well as an output device, wherein for the evaluation of a test strip on which body-specific substances, in particular proteins released in a certain incident in the body, are detected with the help of labelled antibodies, the concentration of the labelled antibodies is determined by a colour change in a strip, wherein the colour intensity (grey level) of the concentration of the antibodies per volume is proportional, the test strip is portrayed with the help of an optic on a CCD comprising areally arranged pixels on one level (individual photo diodes), wherein the intensity in certain directly portrayable colour or grey levels is used for the evaluation and the relative discoloration is compared via calibration values deposited in the programme, wherein the digital pixel information per colour or grey level in the microprocessor is portrayed in its intensity as a column per pixel, wherein the height of the column matches the intensity, an evaluation algorithm is carried out, firstly finding the test strip by scans through the peaks running orthogonal to one another (maximum), defining an area defining the test strip as areas to be detected and integrating over the colour value levels of all these pixels and forming the mean value and these columns being portrayed next to one another on one level such that the distribution of the intensity over the test field is portrayed as a surface contour or surface profile, the sequence of height of which matches the course of intensity of the colour intensity received with the CCD, and reference fields and reference images located next to the test field to be detected on the optical object level of the appliance are recorded by the CCD simultaneously with the image of the sight field of the test with capture line and control line, wherein possible error and aging processes are eliminated by the reference fields and reference images in the appliance by a definition of an area for the white balance being carried out, via which there is also integration and thereafter a difference being formed between pixel integration value and white balance and the value being compared with calibration values deposited in a database and being output as a measured value.

2. Method according to claim 1, wherein a self-calibration (self-test) is done before the start on the basis of the reference fields and reference images and that a test identification is carried out.

3. Method according to claim 1, wherein a peak correction, a noise smoothing, an intensity correction, a filtering for artefacts, an image scaling and rotation correction, a peak recognition, an anti-aging correction and/or a master volume calibration are done in order to eliminate possible error and aging processes.

4. Method according to claim 1, wherein:

a) a self-test is carried out after the appliance is switched on and the test cassette pushed in, wherein the image size is referenced in the reference field, the colour intensity values are referenced and, if necessary, corrected with the values deposited in the memory,

b) the measurement is started and the patient'"'"'s data are input by the operator,

c) the images are recorded by a sensor,

d) an addition of the image lines (integration along the capture line) is done, wherein the image lines are added and mean figures are formed,

e) a peak recognition is carried out, with a reference level being defined for the peak, defining the intensity values for the environment of the test strip

f) this value is displayed.

5. Method according to claim 1, wherein the test is identified on the basis of the barcode attached to the reverse or a data matrix code arranged in the sight field before the measurement by the appliance.

6. Method according to claim 1, wherein recording of the images by the sensor is followed by a self-test of the peak, wherein the point in the test field at which the peak is located is established and the field from which the CCD values are recorded is corrected if need be.

7. Method according to claim 1, wherein:

a multiple measurement is carried out, wherein an averaging over the measured values is done, with the result that the noise of the detector can be equalised and/or

an intensity correction is done by means of a white balance, wherein the measured values for the minimum optical intensity are deducted from the measured values and/or

there is filtering for artefacts, wherein pixel errors and residual noise from the image are minimised by means of a median filter and/or

an image scaling and rotation correction are carried out, wherein a comparison with the reference fields is used to recognise whether the capture line is distorted in the test field and it is corrected by a rotation correction and/or

an area integral is formed for the area between the reference level and the peak, wherein an anti-aging correction is held by comparison of the area integral with the reference curve between minimum and maximum value determined in the self-test (black/white balance) and/or

a master volume calibration is carried out, wherein the measured and integrated value is converted to its calibrated master volume value with master cards inside the appliance with at least one value table with correction values.

8. Method according to claim 1, wherein the location of the test strip to be evaluated is recognised by means of the surface contour or the surface profile with a single linear scan vertical to the expected strips to be detected and/or a further linear scan vertical to the first one is held in the area of the strip to be evaluated for recognition of local changes of intensity and thus the location of the first scanning is corrected such that it runs through the maximum of the test strip.

9. Method according to claim 1, wherein certain demarcated areas within the test field, in which the total and the mean value are formed by integration over the colour value levels of all the pixels contained therein, are defined, wherein an area for a section of the test strip is defined such that no colour change is expected therein and this value is defined as a basic value for later comparisons (so-called white balance) and, for the areas in which a colour change is expected, a sum total value and mean value placed in ratio to the sum and/or total value from the area without colour change are calculated and a value for the concentration of the substance being looked for, preferably protein, is calculated from the ratio in comparison with known calibration values.

10. Method according to claim 1, wherein the portrayal as a surface relief contains the significance of the measurement result (height), the test fluctuations and possible procedure-induced fluctuations and essential knowledge and information are portrayed directly visibly from a portrayal.

11. Method according to claim 1, wherein the areal portrayal is put into connection with the expected outcome and disturbances which could falsify the measurement result such as area disturbances, contaminations or “

pixel errors”

of the CCD are ruled out by means of a software.

12. Method according to claim 1, wherein body fluids or solutions containing components from body fluids are used as initial materials, preferably from blood, serum or urine.

13. Appliance for evaluation of biological tests with various mathematical sequences between change of colour intensity and analyte concentrations, containing an insert, an optic, a reception element with a, CCD matrix of pixels areally arranged on a level as a reception element, a lighting for the test, at least one reference field independent of aging and temperature in the sight field on the image level next to the sight field of the test, which is recorded simultaneously with the image of the sight field of the test and wherein said reference field or reference image have a field with maximum color intensity, a field with minimum color intensity, a variable measurement reference field, color reference fields in the RGB colors and a peak detect reference field on the outer edges, and which can permanently and directly be put into comparison with the test, evaluation electronics containing an evaluation algorithm, a display, an energy supply and electrical interfaces as well as an output device.

14. Appliance according to claim 13 for evaluation of a test strip containing an insert, an optic, a reception element with a CCD matrix of pixels areally arranged on a level as reception element, a lighting for the test, evaluation electronics containing an evaluation algorithm, a display, an energy supply and electrical interfaces as well as an output device, wherein reference fields or reference images have been arranged on the optical object level next to the test field to be detected.

15. Appliance according to claim 13, wherein a digital pixel information can be portrayed with the appliance per colour or grey level in the microprocessor in its intensity as a column per pixel, wherein the column height matches the intensity, and said columns can be portrayed next to one another on one level, with the result that the distribution of the intensity over the test field can be portrayed as a surface contour or surface profile, the sequence of height of which matches the sequence of intensity of the colour intensity received with the CCD.

16. The appliance of claim 13, said appliance implementing a method for evaluation of a test strip with an appliance containing an insert, an optic portraying the image of the test strip onto a receiver, reference fields or reference images, a reception component with a CCD matrix of pixels areally arranged on a level as a reception element, lighting for the test strip, evaluation electronics containing an evaluation algorithm, a display, an energy supply and electrical interfaces as well as an output device, wherein for the evaluation of a test strip on which body-specific substances, in particular proteins released in a certain incident in the body, are detected with the help of labelled antibodies, the concentration of the labelled antibodies is determined by a colour change in a strip, wherein the colour intensity (grey level) of the concentration of the antibodies per volume is proportional, the test strip is portrayed with the help of an optic on a CCD matrix comprising areally arranged pixels on one level (individual photo diodes), wherein the intensity in certain directly portrayable colour or grey levels is used for the evaluation and the relative discoloration is compared via calibration values deposited in the programme, wherein the digital pixel information per colour or grey level in the microprocessor is portrayed in its intensity as a column per pixel, wherein the height of the column matches the intensity, an evaluation algorithm is carried out, firstly finding the test strip by scans through the peaks running orthogonal to one another (maximum), defining an area defining the test strip as areas to be detected and integrating over the colour value levels of all these pixels and forming the mean value and these columns being portrayed next to one another on one level such that the distribution of the intensity over the test field is portrayed as a surface contour or surface profile, the sequence of height of which matches the course of intensity of the colour intensity received with the CCD, and reference fields and reference images located next to the test field to be detected on the optical object level of the appliance are recorded by the CCD simultaneously with the image of the sight field of the test with capture line and control line, wherein possible error and aging processes are eliminated by the reference fields and reference images in the appliance by a definition of an area for the white balance being carried out, via which there is also integration and thereafter a difference being formed between pixel integration value and white balance and the value being compared with calibration values deposited in a database and being output as a measured value.

17. Appliance according to claim 13, wherein it is a mobile and stand-alone appliance.

18. Appliance according to claim 13, wherein it contains a device for identification of test strips, preferably a device for recognition of barcodes or data matrix codes.

19. Appliance according to claim 13, wherein it can be con-figured retroactively for additional tests via mobile memories.

20. Appliance according to claim 13, wherein it contains an internal master calibration.