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This article waslast modified on 10 July 2017.

When a person with chest pain and other signs and symptoms suggestive of a heart attack (myocardial infarction) arrives as an emergency at hospital, a number of tests are done urgently to help decide whether the cause is a heart attack, unstable angina or a problem outside the heart. Usually a physical examination is performed, a clinical history taken and an electrocardiogram (ECG) performed on arrival. A change in the ECG tracing called ST-segment elevation is characteristic of a heart attack that has damaged a large area of heart muscle. With lesser damage there is no ST elevation, and so blood tests are needed to distinguish non-ST elevation myocardial infarction (non-STEMI) from other causes of a patient’s symptoms.

Troponins are proteins in muscle fibres that help to regulate muscle contraction. When there is damage to heart muscle, cardiac troponins I (cTnI) and T (cTnT) are released into the blood. An increase in the troponin concentration with time confirms the diagnosis of non-STEMI. Standard cTnI or cTnT tests need a blood sample to be taken on arrival and a second specimen some hours later, with greatest accuracy after twelve hours, so most patients need to be admitted to hospital. More sensitive troponin tests have been developed that can detect much lower amounts of troponin in blood and can allow a clinical decision to be made in less than three or four hours. We reported in a news item on 20 November 2011 that such tests appeared to hold promise of making hospital admission unnecessary for many patients.

A National Institute for Health and Care Excellence (NICE) project group has now evaluated recent clinical evidence for the value of these high-sensitivity troponin (hs-cTnI and hs-cTnT) tests for the early rule out or diagnosis of acute myocardial infarction in people with acute chest pain. In draft guidance published on 16 May 2014 it recommended the use of high sensitivity tests from two manufacturers, but considered that the evidence for the diagnostic accuracy of a third was inadequate.

Professor Carole Longson, Director of NICE Health Technology Evaluation Centre, said “The increased sensitivity of these tests could mean a reduced length of stay for people without raised levels of troponin, and earlier treatment for those with a confirmed non-STEMI.”

Following consultation, NICE plans to publish final guidance in October 2014.