Immunoassay

• US 20040219604A1
• Filed: 04/07/2004
• Published: 11/04/2004
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: University of Turku
• Original Assignee: University of Turku
• Inventors: Pettersson, Kim, Eriksson, Susann
• Granted Patent: US 7,348,157 B2
• Time in Patent Office: Days
• US Class Current: 435/7.1
• CPC Class Codes: G01N 2333/4712 Muscle proteins, e.g. myosin, actin, protein
• CPC Class Codes: G01N 33/6887 from muscle, cartilage or connective tissue
• CPC Class Codes: Y10S 435/962 Prevention or removal of interfering materials or reactants or other treatment to enhance results, e.g. determining or preventing nonspecific binding
• CPC Class Codes: Y10S 435/967 Standards, controls, materials, e.g. validation studies, buffer systems
• CPC Class Codes: Y10S 435/973 Simultaneous determination of more than one analyte
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials

Abstract

This invention relates to a method for detection and/or quantification of cardiac troponin I (cTnI) in a sample derived from an individual'"'"'s blood, said method being based on a sandwich immunoassay employing at least two capture antibodies and at least one tracer antibody, wherein

a first capture antibody is directed to the N-terminal part of cTnI, to the C-terminal part of cTnI or to the part of the cTnI midfragment, which is slightly affected by the interfering factor, and a second capture antibody is directed to another of the aforementioned parts, and

a tracer antibody is directed to the N-terminal part of cTnI, to the C-terminal part of cTnI or to TnC, which is complexed with cTnI.

Claims

1. Method for detection and/or quantification of cardiac troponin I (cTnI) in a sample derived from an individual'"'"'s blood, said method being based on a sandwich immunoassay employing at least two capture antibodies and at least one tracer antibody, wherein

a first capture antibody is directed to the N-terminal part of cTnI, to the C-terminal part of cTnI or to the part of the cTnI midfragment, which is slightly affected by the interfering factor, and a second capture antibody is directed to another of the aforementioned parts, and

a tracer antibody is directed to the N-terminal part of cTnI, to the C-terminal part of cTnI or to TnC, which is complexed with cTnI.

2. The method according to claim 1, wherein a first capture antibody is directed to the part of the cTnI midfragment, which is slightly affected by the interfering factor and a second capture antibody is directed to the N-terminal or to the C-terminal part of cTnI, and a tracer antibody is directed to the C-terminal part of cTnI.

3. The method according to claim 2 wherein the first capture antibody is directed to the epitope region 30-70 aa, preferably 41-49aa, the second capture antibody is directed to the epitope region 148-209 aa, preferably 190-196 aa, and the tracer antibody is directed to the epitope 110-148 aa, preferably 137-148.

4. The method according to claim 1, wherein the first capture antibody is directed to the part of the cTnI midfragment, which is slightly affected by the interfering factor and a second capture antibody is directed to the C-terminal part of cTnI, and a third capture antibody is directed to the N-terminal part of cTnI, and the tracer antibody is directed to TnC.

5. The method according to claim 4 wherein the first capture antibody is directed to the epitope region 30-70 aa, preferably 41-49 aa, the second capture antibody is directed to the epitope region 148-209 aa, preferably 190-196 aa, and the third capture antibody is directed to the epitope region 1-29 aa, preferably 23-29 aa.

6. The method according to claim 1 wherein the capture antibody or capture antibodies are attached to a solid surface and the method is carried out as a heterogeneous assay, either in one step or in several steps.

7. The method according to claim 1 wherein the capture antibody or capture antibodies are attached to a small particle or a molecule, and the method is carried out as a homogeneous assay.

8. The method according to claim 7, wherein the capture antibody or capture antibodies are attached to a molecule, preferably a luminescent lanthanide chelate and the method is carried out as a homogeneous energy transfer assay.

9. The method according to claim 1 wherein the sample is serum, plasma or whole blood.