Methods for improving the recovery of troponin i and t in mebranes, filters and vessels

A method for performing a sandwich immunoassay for troponin I or troponin T in-a sample from a patient suspected of having had a myocardial infarction, said method comprising:

• a. contacting the sample with (i) a first antibody that binds said troponin I or troponin T, (ii) with a labeled second antibody that binds said troponin I or troponin T, and (iii) with troponin C added to the sample as an aqueous solution or with troponin C dried to a surface that is brought into contact with, and thereby dissolves into, the sample;
• and
• b. detecting sandwich complexes formed by binding of said first and second antibodies with said troponin I or troponin T by detecting a signal from said label present in said complexes.