Troponin I and Troponin T are regulatory proteins found in the heart muscle and are released into the blood stream when there is some form of damage to the heart. Cardiac troponin levels are normally so low they cannot be detected with most blood tests. Troponin I test is usually required to diagnose heart attack and any other conditions with similar signs and symptoms. Trop I testing may also be done for people with angina to monitor their symptoms. These tests may be done along with other cardiac biomarker tests such as CK-MB or myoglobin.