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Troponin test


Definition:

The troponin test measures the levels of certain proteins called troponin T and troponin I in the blood. These proteins are released when the heart muscle has been damaged, such as a heart attack. The more damage there is to the heart, the greater the amount of troponin T and I there will be in the blood.

Alternative Names:

TroponinI; TnI; TroponinT; TnT; Cardiac-specific troponin I; Cardiac-specific troponin T; cTnl; cTnT

How the test is performed:

A blood sample is needed.

How to prepare for the test:

Usually, no special preparation is necessary.

How the test will feel:

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Normal Values:

Cardiac troponin levels are normally so low they cannot be detected with most blood tests.

Your test results are usually considered normal if the results are:

  • Troponin I : less than 10 µg/L
  • Troponin T : 0–0.1 µg/L

Normal troponin levels 12 hours after chest pain has started mean a heart attack is unlikely.

 

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean:

An increase in the troponin level, even a slight one, usually means there has been some damage to the heart. Significantly high levels of troponin are a sign that a heart attack has occurred.

Most patients who have had a heart attack have increased troponin levels within 6 hours. After 12 hours almost everyone who has had a heart attack will have raised levels.

Troponin levels may remain high for 1 to 2 weeks after a heart attack.

Increased troponin levels may also be due to:

  • Abnormally fast heart beat
  • High blood pressure in lung arteries (pulmonary hypertension)
  • Blockage of a lung artery by a blood clot, fat, or tumor cells (pulmonary embolus)
  • Congestive heart failure
  • Coronary artery spasm
  • Inflammation of the heart muscle usually due to a virus (myocarditis)
  • Strenuous exercise (for example, due to marathons or triathlons)
  • Trauma that injures the heart such as a car accident
  • Weakening of the heart muscle (cardiomyopathy)

Increased troponin levels may also result from certain medical procedures such as:

  • Cardiac angioplasty/stenting
  • Heart defibrillation or electrical cardioversion (purposeful shocking of the heart by medical personnel)
  • Open heart surgery
  • Radiofrequency ablation of the heart
What the risks are:

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)
Special considerations:

Increased troponin levels may also be seen in people with certain chronic health conditions such as heart failure, long-term kidney disease, and stable heart disease. Increased levels in these and other conditions can be a sign that a patient is at increased risk for bad outcomes.

References:

AndersonJL. ST segment elevation acute myocardial infarction and complications of myocardial infarction. In: Goldman L, Schafer AI, eds.Cecil Medicine. 24th ed.Philadelphia,PA: Saunders Elsevier; 2011:chap 73.

Kushner FG, et al. 2009 Focused Updates:ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update).Circulation. 2009;120:2271-2306.

Patil H, Vaidya O and Bogart D. A review of causes and systemic approach to cardiac troponin elevation.Clin Cardiol. 2011 Dec;34(12):723-8.

Sabatine MS, Cannon CC. Approach to the patient with chest pain. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds.Bonow: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine.9th ed. Saunders; 2011:chap 53.


Review Date: 1/11/2012
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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