Assay for analytes using multiple receptors

Patent metadata

Field	Value
Publication number	US-10088490-B2
Application number	US-86060010-A
Country	US
Kind code	B2
Filing date	Aug 20, 2010
Priority date	Aug 20, 2010
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A method for determining an analyte in a sample suspected of containing the analyte comprises providing in combination a medium, the sample, and two or more different receptors. Each different receptor binds to at least two different epitopic sites. One of the epitopic sites is a common binding site and one of the epitopic sites is non-common binding site. The non-common epitopic sites are different for each different receptor. The receptors exhibit mono-molecular binding. The medium is incubated under conditions for binding of the receptors to the epitopic sites. The medium is examined for the presence and/or amount of complexes comprising the epitopic sites and the receptors. The presence and/or amount of the complexes indicate the presence and/or amount of the analyte in the sample.

First claim

What is claimed is:

1. A method for determining an amount of cortisol in a sample suspected of containing cortisol and different interfering substances, the method consisting essentially of:
(a) combining in an aqueous medium:
(i) the sample, and
(ii) two or more different antibody-tracer conjugates wherein the tracer of each different conjugate is the same and wherein the antibody of each different conjugate is different and wherein each different antibody binds to at least two different epitopic sites wherein one of the epitopic sites is a binding site of cortisol that is a common binding site bound by all of the antibodies, and another of the epitopic sites is a binding site of one or more of the interfering substances that is a non-common binding site that is different for each different antibody and wherein each different antibody of the antibody-tracer conjugates is preselected for its binding profile to cortisol and to one or more of the interfering substances and wherein each different antibody exhibits a binding affinity to a portion of the interfering substances wherein the portion of interfering substances comprises about 10% to about 90% of the total number of interfering substances in a sample and wherein the number of interfering substances in one portion that have low binding affinity for two different antibodies is no greater than about 10 and wherein low binding affinity means that an interfering substance has a binding affinity for one of the antibodies that is no greater than about 80% of the binding affinity of cortisol for said one of the antibodies,

(b) incubating the medium under conditions for binding of the different antibodies to the epitopic sites,
(c) examining the medium for an amount of signal from the complexes comprising the epitopic sites and the antibody-tracer conjugates, and
(d) comparing the amount of the signal to a calibration curve to determine the true amount of cortisol in the sample,

wherein the interfering substances are selected from the group consisting of aldosterone, allotetrahydrocortisol, corticosterone, cortisone, α-cortol, β-cortol, α-cortolone, β-cortolone, dehydrocorticosterone, 11-deoxycorticosterone, 11-deoxycortisol, 21-deoxycortisol, 21-deoxycortisone, dexamethasone, 5β-dihydrocortisol, 20α-dihydrocortisol, 20β-dihydrocortisol,
20α-dihydrocortisone, 20β-dihydrocortisone, fluorocortisone acetate, 6β-hydroxycortisol, 11β-hydroxy-etiocholanolone, 17β-hydroxypregnenolone, 17α-hydroxyprogesterone, 11β-hydroxyprogesterone, 11-ketoetiocholanolone, 6-methyl-prednisolone, prednisolone, prednisone, progesterone, sulphate 21-cortisol, tetrahydrocortisol, tetrahydrocortisone, and tetrahydro-11-deoxycortisol.

2. The method according to claim 1 wherein the sample is a body excretion, body aspirant, body excisant or body extractant.

3. The method according to claim 1 wherein the tracer is a member of a signal producing system, a member of a specific binding pair, or a complex of members of a specific binding pair.

4. The method according to claim 1 wherein the method is a homogeneous assay method.

5. The method according to claim 1 wherein the antibodies are preselected by a process comprising conducting for each antibody an assay for cortisol in an assay medium comprising cortisol and one of the interfering substances and determining a percent cross-reactivity of the antibody for the interfering substance and repeating the assay for each different interfering substance to prepare a cross-reactivity profile and selecting for use in the method the two or more different antibodies.

Assignees

• Lewisch Sandra A
• Schiavoni Lynn M
• Bedzyk William D
• Siemens Healthcare Diagnostics Inc

Inventors

• Lewisch Sandra A
• Schiavoni Lynn M
• Bedzyk William D

Classifications

• G01N33/9493 Primary

  Immunosupressants · CPC title

• G01N33/536

  with immune complex formed in liquid phase · CPC title

• G01N33/743 Primary

  Steroid hormones · CPC title

• G01N33/5306

  Improving reaction conditions, e.g. reduction of non-specific binding, promotion of specific binding · CPC title