How is it used?
Troponin levels are used in persons who have Chest pain to see if they have had a Heart Attack or other heart damage. Chest pain can be due to heart problems, too much stomach acid, strain on chest muscles, or other causes. Normally, if the heart does not get enough oxygen, it causes chest pain during exercise. This pain, which is usually due to gradual build up of fat in the walls of the blood vessels [Atherosclerosis, or hardening of the arteries] and which stops when a persons rests, is called exertional angina.
Sometimes, a small blood clot forms in a blood vessel, causing chest pain that occurs while a person is at rest, or which continues after exercise stops. If the blood clot dissolves on its own, the chest pain will stop; this condition is called unstable angina. In a Heart Attack, the blood clot remains and heart muscle cells die, and release their contents, including troponin, myoglobin, and CK. In Unstable angina, the heart cells may also release troponin. Studies have shown that people who have unstable angina and high troponin, but normal CK, CK-MB, and myoglobin, have a higher risk of having a Heart Attack or other serious heart problem in the next few months. Many doctors now check troponin in persons with unstable angina to identify those who may benefit from such treatments as angioplasty (using a balloon to open a blocked heart blood vessel) or heart bypass surgery.
When is it ordered?
Troponin tests are usually ordered, often along with other heart tests such as CK, CK-MB, or myoglobin, in persons who have prolonged chest pain or pain that occurs at rest. Typically, troponin is done 2 or 3 times during a 12- to 16-hour period.
What does the test result mean?
NOTE: A standard reference range is not available for this test. Because reference values are dependent on many factors, including patient age, gender, sample population, and test method, numeric test results have different meanings in different labs. Your lab report should include the specific reference range for your test. Lab Tests Online strongly recommends that you discuss your test results with your doctor. For more information on reference ranges, please read Reference Ranges and What They Mean.
Normally, troponin levels are very low; even slight elevations indicate some damage to the heart-either Unstable angina or Heart Attack. Troponin will remain high for 1-2 weeks after a heart attack. Troponin is not generally affected by damage to other muscles, so that muscle injections, accidents, strenuous exercise, and drugs that can damage muscle do not affect troponin levels.
Is there anything else I should know?
Troponin levels may be slightly elevated in persons with kidney failure. Because troponin levels are normally very low, slight elevations can sometimes be due to factors that interfere with the test. Sometimes, if a person is getting a drug called heparin (often used to treat suspected unstable angina or heart attack), a falsely high troponin can occur with some test methods. Generally, troponin T and troponin I results both indicate a similar amount of heart damage; different laboratories typically will only use one or the other test.
What are the other heart attack tests?
Doctors often use more than one test to determine if a person who has chest pain is having a heart attack. Troponin is generally considered the most accurate test, and CK-MB (the heart isoenzyme of CK) is also highly accurate in detecting damage to the heart, even when there is no other evidence of a heart attack. Myoglobin and Creatine Kinase almost always rise in patients with a heart attack, but they are less specific - other conditions can also produce an increase in these two tests.
Revision date: July 6, 2011
Last revised: by Jorge P. Ribeiro, MD