Cardiac-specific TnI (cTnI) is encoded by a gene separate from the gene that encodes troponin-I. After translation, a 31-amino acid chain is added to the amino-terminal end. This chain makes troponin-I cardiac specific.
It is measured as an early indicator of an AMI because it is usually released and detectable within 4 – 6 hours following myocardial damage and peaks around 24 hours. It remains elevated in peripheral blood for 3 – 7 days and can be elevated as long as 14 days.
