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Also known as: TnI; TnT; cTnI; cTnT
Formal name: Cardiac-specific Troponin I and Troponin T

At a Glance

Why Get Tested?

To determine if you have had a heart attack or injury to heart muscle

When to Get Tested?

Immediately, then followed by a series of troponin tests over several hours if you are having chest pain or other symptoms that may be due to a heart attack

Sample Required?

A blood sample drawn from a vein in the arm

Test Preparation Needed?


The Test Sample

What is being tested?

The troponins are a family of proteins found in skeletal and heart muscle (cardiac) fibers. There are three different types: troponin C (TnC), troponin T (TnT), and troponin I (TnI). Together, these three proteins regulate muscular contraction.

Cardiac-specific troponins I and T (cTnI and cTnT) are troponins that are found only in the heart. They are normally present in very small to undetectable quantities in the blood. When there is damage to heart muscle cells, cardiac-specific troponins I and T are released into circulation. The more damage there is, the greater their concentration in the blood. The troponin test measures the amount of cardiac-specific troponin I or T in the blood and is used to help determine if an individual has suffered a heart attack.

When a person has a heart attack, levels of cardiac-specific troponins I and T can become elevated in the blood within 3 or 4 hours after injury and may remain elevated for 10 to 14 days.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Zieve, D. (Updated 2010 March 15). Troponin Test. MedlinePlus Medical Encyclopedia [On-line information]. Available online at Accessed September 2011.

(2011 March 1). What Is a Heart Attack? National Heart Lung and Blood Institute [On-line information]. Available online at through Accessed September 2011.

Mayo Clinic staff (2010 November 12). Heart attack. [On-line information]. Available online through Accessed September 2011.

Zafari, A. M. and Afonso, L. (Updated 2011 September 14). Myocardial Infarction. Medscape Reference [On-line information]. Available online through Accessed September 2011.

Grenache, D. et. al. (Updated 2011 January). Ischemic Heart Disease. ARUP Consult [On-line information]. Available online through Accessed September 2011.

(© 1995-2011). Unit Code 82428: Troponin T, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online through Accessed September 2011.

Beavers, C. (2010 February 1). Update on Cardiac Markers—Diagnosing AMI Using Troponin. CAP NewsPath [On-line information]. Available online through Accessed September 2011.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 978-980.

Morrow D, Antman E. Evaluation of High-Sensitivity Assays for Cardiac Troponin. Clinical Chemistry. 2009;55:5-8. Available online at through Accessed November 2011.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Adams, J. & Apple, F. (2004). New Blood Tests for Detecting Heart Disease. American Heart Association, from Circulation 2004;109:e12-e14. PDF available for download at through

Achar, S. et. al. (2005 July 1). Diagnosis of Acute Coronary Syndrome. American Family Physician. Available online at through

(2000). Cardiac Troponin-I Assay. UCLA Diagnostic Module-2000. PDF available for download at'intitle:Troponin' through

Jeremias, A. and Gibson, C. M. (2005 May 3). Narrative Review: Alternative Causes for Elevated Cardiac Troponin Levels when Acute Coronary Syndromes Are Excluded. Annals of Internal Medicine v 142 (9).

Check, W. (2001 July). Troponin triple crown: diagnosis, risk, Rx. College of American Pathologists, CAP Today. Available online at through

Parham, S. (2005 February). Clearing a path for new cardiac markers. College of American Pathologists, CAP Today. Available online at through

American Family Physician: Diagnosis of Acute Coronary Syndrome. Available online at through

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC, p. 264.

Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006, pp 522-525.

Mehta S, Bautista RM, Adams BD. Role of first-drawn indeterminate troponin-I levels in the Emergency Department. Int J Cardiol 2008 Mar 18.

Michielsen Etienne C H J, Wodzig Will K W H, Van Dieijen-Visser Marja P.
 Cardiac troponin T release after prolonged strenuous exercise.
 Sports medicine (Auckland, N.Z.) 2008; 38(5):425-35.

Lippi G, Schena F, Salvagno GL, Montagnana M, Gelati M, Tarperi C, Banfi G, Guidi GC. Influence of a half-marathon run on NT-proBNP and troponin T. Clin Lab. 2008; 54(7-8):251-4.

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