Filter paper treatment for improved diagnostic assays

• US 6,309,887 B1
• Filed: 01/27/1999
• Issued: 10/30/2001
• Est. Priority Date: 01/27/1998
• Status: Expired due to Fees

• Current Assignee: Flexsite Research And Development, LLC
• Original Assignee: Flexsite Diagnostics, Inc.
• Inventors: Ray, Robert A.
• Primary Examiner(s): WALLENHORST, MAUREEN
• Application Number:
  US09/238,114
• Time in Patent Office: 1,007 Days
• Field of Search: 436/63, 436/66, 436/67, 436/69, 436/164, 436/169, 436/177, 436/178, 422/55, 422/56, 422/68.1, 422/73, 422/99, 422/101
• US Class Current: 436/67
• CPC Class Codes: G01N 33/721 Haemoglobin
• CPC Class Codes: G01N 33/723 Glycosylated haemoglobin

Abstract

Filter paper absorbed with a solution of anticoagulant, e.g., ethylene diamine tetra-acetic acid (EDTA), then dried, useful for collection of a blood sample for analysis of hemoglobin or a hemoglobin fraction in the sample showed higher precision in standard assays than untreated filter paper. Methods of using the anticoagulant-treated filter paper are also described.

Claims

1. A method for assaying a hemoglobin in a liquid biological sample, said method comprising:

providing a material for absorbing the biological sample comprising the hemoglobin, the material containing a chelating agent for preventing the liquid biological sample from coagulating;

applying the liquid biological sample to the chelating agent-containing material;

allowing the liquid biological sample to dry into a dried biological sample on the material;

eluting the dried biological sample from the material, whereby tile chelating agent facilitates elution of the dried biological sample from the material to improve the precision of the method; and

assaying the hemoglobin in the eluted dried biological sample.

2. The method according to claim 1, wherein said step of allowing, the liquid biological sample to dry into a dried biological sample on the material is accomplished in a time period of at least approximately twenty-four hours.

3. The method according to claim 1, wherein the material is filter paper.

4. The method according to claim 3, wherein the filter paper is cellulose based.

5. The method according to claim 1, wherein the liquid biological sample is blood.

6. The method according to claim 5, wherein the chelating agent is citric acid.

7. The method according to claim 1, wherein the hemoglobin is a glycohemoglobin.

9. The method according to claim 1, wherein the chelating agent is ethylenediamine tetra-acetic acid.

10. The method according to claim 9, wherein the liquid biological sample is blood and the ethylenediamine tetra-acetic acid is applied to the material in a quantity of at least 5 μ

g/20 μ

l of blood to prevent coagulation of the blood.

11. The method for assaying a hemoglobin in a liquid biological sample according to claim 6, wherein the liquid biological sample is blood and the ethylenediamine tetra-acetic acid is applied to the material in a quantity of at least 10 μ

g/20 μ

l of blood to prevent coagulation of the blood.

12. The method according to claim 1, wherein the chelating agent is present in a quantity sufficient to prevent coagulation of the liquid biological sample applied to the material.

8. The method 7, wherein the glycohemoglobin is HbA1c.