Novel methods for the assay of troponin i and t and complexes of troponin i and t and selection of antibodies for use in immunoassays

Abstract

Assay systems and specialized antibodies for the detection and quantitation of troponin I and troponin T in body fluids as an indicator of myocardial infarction. Since troponin I and T exist in various conformations in the blood, the ratios of the monomeric troponin I an T and the binary and ternary complexes, as well as which form of troponin present in the blood, may be related to the metabolic state of the heart. Disclosed is a system to determine the presence of a troponin form or a group of troponin forms in a sample of whole blood, serum or plasma. Also disclosed are antibodies which recognize, unbound troponin forms, the forms of troponin in binary complexes, the ternary complex of troponin I, T and C, and the conformations of troponin I having intramolecularly oxidized and reduced cysteines.

1 . A method of increasing assay sensitivity in a cardiac troponin immunoassay, comprising:
 providing an agent to reduce non-specific adsorption of cardiac troponin I in a body fluid sample obtained from a human subject to components of an assay device,
 wherein said agent that reduces non-specific adsorption increases assay sensitivity for troponin I. 
   
     
     
         2 . The cardiac troponin assay method according to  claim 1 , wherein the agent that reduces non-specific adsorption of troponin I is melittin. 
     
     
         3 . The cardiac troponin assay method according to  claim 1 , wherein the agent that reduces non-specific adsorption of troponin I is protamine. 
     
     
         4 . The cardiac troponin assay method according to  claim 1 , wherein the agent that reduces non-specific adsorption of troponin I is combination of melittin and protamine. 
     
     
         5 . The cardiac troponin assay method according to  claim 2  or  4 , wherein the melittin is provided at a concentration of between about 0.017 mM to about 0.05 mM. 
     
     
         6 . The cardiac troponin assay method according to  claim 3  or  4 , wherein the protamine is provided at a concentration of between about 0.03 mg/mL to about 0.1 mg/mL. 
     
     
         7 . The cardiac troponin assay method according to  claim 6  wherein assay response is increased by factors of 30% to 400% compared to an assay without an agent that reduces non-specific adsorption.