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 3 - 7 days and can be elevated as long as 14 days.