Method for detection of vitamin d metabolites

• US 20040096900A1
• Filed: 12/17/2003
• Published: 05/20/2004
• Est. Priority Date: 12/06/2000
• Status: Active Grant

• Current Assignee: Immunodiagnostic Systems Ltd. (Revvity, Inc.)
• Original Assignee: Immunodiagnostic Systems Ltd. (Revvity, Inc.)
• Inventors: Laurie, David, Gardner, Michael James, Barnes, Alexander Kirkley
• Granted Patent: US 7,482,162 B2
• Time in Patent Office: Days
• US Class Current: 435/7.1
• CPC Class Codes: G01N 33/82 involving vitamins or their receptors
• CPC Class Codes: Y10S 436/817 Steroids or hormones
• CPC Class Codes: Y10S 436/825 Pretreatment for removal of interfering factors from sample
• CPC Class Codes: Y10S 436/826 Additives, e.g. buffers, diluents, preservatives
• CPC Class Codes: Y10T 436/108331 Preservative, buffer, anticoagulant or diluent
• CPC Class Codes: Y10T 436/25 including sample preparation
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction

Abstract

The present invention relates to a method for measuring the amount of vitamin D metabolite in a sample of plasma or serum, comprising the step of (a) adding to a serum or plasma sample a non-competitive displacement agent to effect separation of any vitamin D metabolite in the sample form protein to which it is bound, such that any vitamin D metabolite may be detected and/or measured; and (b) detecting or measuring the amount of vitamin D metabolite in the sample of (a). Such methods are useful in determining the vitamin D status of the subject, for example in the diagnosis of disease. Also provide are agents and kits for use in performing the methods of the invention.

Claims

1. A method for measuring vitamin D metabolite present in a plasma or serum sample, the method comprising:

(a) adding to a serum or plasma sample a non-competitive displacement agent to effect separation of any vitamin D metabolite in the sample from protein to which it is bound, such that any vitamin D metabolite may be detected and/or measured; and

(b) detecting or measuring the amount of vitamin D metabolite in the sample of (a).

2. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 1, wherein the vitamin D metabolite is 25-hydroxy Vitamin D or an analogue thereof.

3. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 1 or 2, wherein the non-competitive displacement agent is a chemical reagent.

4. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 3 wherein the displacement agent comprises 8-anilino-1-napthalenesulphonic acid ammonium salt, 3-(acetonylbenzyl)-4-hydroxycoumarin and a water miscible solvent.

6. A method for measuring vitamin D metabolite in a serum or plasma sample according to any one of claims 1 to 5 wherein the amount of vitamin D metabolite is measured in a binding assay.

7. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 6 wherein the binding assay is a competitive binding assay.

8. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 7 wherein the competitive binding assay comprises the steps of

(a) providing a support having immobilised thereon a binding factor capable of binding a vitamin D metabolite;

(b) contacting the support with a sample comprising the vitamin D metabolite to be measured;

(c) contacting the support with a labeled form of the vitamin D metabolite;

(d) measuring the amount of labeled vitamin D metabolite left bound to the support,

wherein the amount of labeled vitamin D metabolite bound to the support is proportional to the amount of vitamin D metabolite in the sample.

9. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 8, wherein the binding factor immobilised on the support is DBP.

10. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 8, wherein the binding factor immobilised on the support is an anti-vitamin D metabolite antibody.

11. A method for measuring vitamin D metabolite in a serum or plasma sample according to any one of claims 8 to 10, wherein the vitamin D metabolite is labeled with biotin, avidin, a fluorescent molecule, or a chemiluminescent molecule.

12. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 6, wherein the binding assay is an immunoassay.

13. A method for determining the vitamin D status of a subject, comprising the method according to any one of claims 1 to 12.

14. A method for determining the vitamin D status of a subject according to claim 13 comprising the additional step of first removing a sample from a subject.

15. A non-competitive displacement agent according to any one of claims 3 to 5.

16. Use of a non-competitive displacement agent according to claim 15 in measuring the vitamin D metabolite in a serum or plasma sample.

17. Use of a non-competitive displacement agent according to claim 15 in a method according to any one of claims 1 to 14.

18. A kit for use in measuring vitamin D metabolite in a sample comprising a displacement agent according to claim 15.

19. A kit according to claim 18 further comprising a key showing the correlation between the results of the method and the amount of vitamin D metabolite present in the sample.

20. A kit according to claim 18 or 19 further comprising means for measuring the vitamin D metabolite present in the sample.

21. A kit according to any one of claims 18 to 20 further comprising one or more of a support, labels, protein, antibody and instructions for use.

5. A method for measuring vitamin D metabolite in a serum or plasma sample according to claim 5, wherein the water miscible solvent is methanol.