In the first step the serum sample and the Conjugate are added to the microplate coated with Streptavidin. The conjugate in this Troponin I ELISA Assay Kit contains two monoclonal antibodies direct against different epitopes of Troponin I: one is biotinylated, the other one is bound to the horseradish peroxidase (HRP); these antibodies compete for the native Troponin I in the sample, thus at the end of first step a sandwich between the antibodies and the Troponin I is formed; this complex binds to the microplate wells through the specific interaction between biotine and streptavidin. Sample Types: serum. Range: 1- 30 ng/ml. Sensitivity: 0.3 ng/ml. Time: 0.5 hours ? Troponin I is a 24kDa protein and is part of a complex, called Troponin complex, that regulates the calcium-modulate interaction between actin and myosin in the striated muscle; this complex is an heterodimer consisting of Troponin C, I and T; Troponin I is the inhibitory subunit of this complex. Troponin complex is tightly bound to the contractile apparatus, but many studies shows that the Troponin I is released into the blood circulation in case of myocardial damage, such as in AMI (Acute Myocardial Infarction), where the myofibril is seriously damaged. The presence of Troponin I in the circulation can be detected for many days after AMI, thus the detection of Troponin levels in blood fluids is an excellent biomarker for myocardial damage. It should be noted that in case of marathon runners or other skeletal injury, the Troponin I has not been found in circulation, thus it is a very specific marker for AMI.