Reagent combination and method for direct test strip measurement of cholesterol from low density lipoproteins at ambient temperatures

• US 20050170447A1
• Filed: 10/11/2004
• Published: 08/04/2005
• Est. Priority Date: 02/03/2004
• Status: Active Grant

• Current Assignee: Polymer Technology Systems Incorporated (Sinocare, Inc.)
• Original Assignee: Polymer Technology Systems Incorporated (Sinocare, Inc.)
• Inventors: Lawrence, Gregory M., Pasqua, John
• Granted Patent: US 7,435,577 B2
• Time in Patent Office: Days
• US Class Current: 435/11
• CPC Class Codes: G01N 2800/044 Hyperlipemia or hypolipemia, e.g. dyslipidaemia, obesity
• CPC Class Codes: G01N 33/526 the element being adapted for a specific analyte
• CPC Class Codes: G01N 33/92 involving lipids, e.g. cholesterol , lipoproteins, or their receptors steroid hormones G01N33/743

Abstract

Cholesterol from Low Density Lipoproteins (LDL-C) is measured directly with a test strip at room temperature using a reagent that takes advantage of the varying surface charge density on LDLs and non-LDLs to selectively make LDL-C available for testing.

Claims

1. A room-temperature method for directly determining the concentration of LDL cholesterol in whole blood, plasma or serum comprising contacting the sample with reagents that selectively make LDL-C available for detection.

2. The method of claim 1, wherein the reagents react differently with LDLs and non-LDLs as a function of the relative surface charge density on LDLs and non-LDLs in the sample.

3. The method of claim 1, wherein the reagents comprise cations, polyanions, cyclodextrin derivatives, a copolymeric surfactant and a surfactant for the copolymeric surfactant.

4. The method of claim 3, wherein the cations include a divalent metal.

5. The method of claim 4, wherein the divalent metal is magnesium.

6. The method of claim 3, wherein the cations include a positively charged amine effective to bind lipoproteins.

7. The method of claim 6, wherein the amine is triethanolamine hydrochloride.

8. The method of claim 3, wherein the polyanion is dextran sulfate.

9. The method of claim 3, wherein the cyclodextrin derivative is alpha cyclodextrin sulfate.

10. The method of claim 3, wherein the copolymeric surfactant is a polyoxyethylene-polyoxypropylene-polyoxyethylene hybrid, having a molecular weight range from about 2,100 to about 6,000 with a preponderance of polyoxyproylene.

11. A combination of reagents suitable for use on a test strip that can selectively cause LDL-C to become available for measurement.

12. The reagent combination of claim 11, comprising cations, polyanions, cyclodextrin derivatives, a copolymeric surfactant and a surfactant for the copolymeric surfactant.

13. The reagent combination of claim 12, wherein the cations include a divalent metal.

14. The reagent combination of claim 12, wherein the divalent metal is magnesium.

15. The reagent combination of claim 12, wherein the cations include a positively charged amine effective to bind lipoproteins.

16. The reagent combination of claim 15, wherein the amine is triethanolamine hydrochloride.

17. The reagent combination of claim 11, wherein the polyanion is dextran sulfate.

18. The reagent combination of claim 11, wherein the cyclodextrin derivative is alpha cyclodextrin sulfate.

19. The reagent combination of claim 11, wherein the copolymeric surfactant is a polyoxyethylene-polyoxypropylene-polyoxyethylene hybrid, having a molecular weight range from about 2,100 to about 6,000 with a preponderance of polyoxyproylene.

20. The reagent combination of claim 11, wherein the reagents include a high molecular weight blocking copolymer surfactant effective to bind non-LDLs and a low molecular weight surfactant effective to increase the solubility of the blocking copolymer surfactant.

21. A vertical flow test strip for use in the direct detection of cholesterol produced from low density lipoproteins in a whole blood, plasma or serum sample, the test strip comprising:

a) a membrane for blocking or slowing the progress of red blood cells through the test strip;

b) a supply of a combination of reagents that can selectively cause LDL-C to become available for measurement; and

c) a cholesterol detection membrane.

22. The test strip of claim 21, comprising cations, polyanions, cyclodextrin derivatives, a copolymeric surfactant and a surfactant for the copolymeric surfactant.

23. The test strip of claim 22, wherein the cations include a divalent metal.

24. The test strip of claim 22, wherein the divalent metal is magnesium.

25. The method of claim 22, wherein the cations include a positively charged amine effective to bind lipoproteins.

26. The method of claim 25, wherein the amine is triethanolamine hydrochloride.

27. The test strip of claim 21, wherein the polyanion is dextran sulfate.

28. The test strip of claim 21, wherein the cyclodextrin derivative is alpha cyclodextrin sulfate.

29. The test strip of claim 21, wherein the copolymeric surfactant is a polyoxyethylene-polyoxypropylene-polyoxyethylene hybrid, having a molecular weight range from about 2,100 to about 6,000 with a preponderance of polyoxyproylene.

30. The test strip of claim 21, wherein the reagents include a high molecular weight blocking copolymer surfactant effective to bind non-LDLs and a low molecular weight surfactant effective to increase the solubility of the blocking copolymer surfactant.

31. The test strip of claim 21, wherein the blocking membrane is impregnated with at least some of the supply of a combination of reagents.

32. The test strip of claim 21, further comprising at least one intermediate membrane impregnated with at least some of the supply of a combination of reagents.