READ-OUT METHOD AND APPARATUS

• US 20100284583A1
• Filed: 08/21/2008
• Published: 11/11/2010
• Est. Priority Date: 08/22/2007
• Status: Active Grant

• Current Assignee: Phadia AB (Thermo Fisher Scientific Incorporated)
• Original Assignee: Phadia AB (Thermo Fisher Scientific Incorporated)
• Inventors: Ljung, Arne
• Granted Patent: US 8,611,619 B2
• Time in Patent Office: Days
• US Class Current: 382/128
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• CPC Class Codes: G01N 33/54386 Analytical elements

Abstract

A read-out method for a diagnostic point-of-care assay device, the device including a read-out substrate having at least one response area capable of producing a coloured indication of a response, the response area including a marker at least one marker whose colour changes in response to binding of an analyte thereto and which is used for indication of response. The method includes registering an image of the response area; calculating a colour saturation value S for the image using at least two distinct wavelengths; using the S-value for determining a result of the assay. A read-out system (10) for an allergy point-of-care assay device is described. The system includes an illumination device (12; 21, 22) capable of delivering at least two different wavelengths of light; a colour image capturing device (14); a control unit (19) for calculating a colour saturation value on images recorded by the colour image capturing device.

Claims

1. Read-out method for a diagnostic point-of-care assay device, the device comprising a read-out substrate having at least one response area capable of producing a coloured indication of a response, the response area comprising a marker at least one marker the colour of which changes in response to binding of an analyte thereto and which is used for indication of response, the method comprising the steps of:

registering an image of said response area;

calculating a colour saturation value S for said image using at least two wavelength ranges;

using the S-value for determining a result of the assay.

2. The method as claimed in claim 1, wherein S-values are compared with a selected threshold value G.

3. The method as claimed in claim 1, wherein S-value(s) is/are correlated to a physical quantity to obtain a value for said physical quantity.

4. The method as claimed in claim 1, wherein the wavelengths are selected such that one wavelength has an absorption maximum for the marker used in the assay, and the other wavelengths have a significantly lower absorption for the marker.

5. The method as claimed in claim 2, wherein two wavelengths are used.

6. The method as claimed in claim 1, wherein the marker is a gold conjugate.

7. The method as claimed in claim 1, wherein the S-value is calculated as

8. The method as claimed in claim 7, wherein the image of the response area is subdivided in a number of sub-strips.

9. The method as claimed in claim 8, wherein the number of sub-strips is between 20 and 30, suitably the number of strips is 5-25, more preferably 8-20, most preferred 10-15.

10. The method as claimed in claim 7, wherein peak values are determined for each sub-strip and for all allergen lines together with background values, the difference between peak and background is calculated for each line and strip, and all sub-strips are compared and the highest value for a respective line, is selected as a “

true”

value for that line.

14. The method as claimed in claim 8, wherein peak values are determined for each sub-strip and for all allergen lines together with background values, the difference between peak and background is calculated for each line and strip, and all sub-strips are compared and the highest value for a respective line, is selected as a “

true”

value for that line.

11. A read-out system (10) for an allergy point-of-care assay device (17, 18), the system comprising

an illumination device (12;

21, 22) capable of delivering at least two different wavelengths of light;

a colour image capturing device (14);

a control unit (19) for calculating a colour saturation value (S) on images recorded by the colour image capturing device.

12. The read-out system as defined in claim 11, wherein the illumination device comprises at least two light sources (21, 22) delivering light of different wave-lengths.

13. The read-out system as defined in claim 11, wherein the illumination device comprises a source of white light and at least two filters for filtering out selected wavelengths from an image.