Troponin for acute coronary syndromes: has NICE got it right?

The guidelines on the use of glycoprotein IIb/IIIa inhibitors for acute coronary syndromes issued by the National Institute for Clinical Excellence (NICE) recommend that blood troponin is used to identify patients who might benefit from therapy. There are, however, a number of circumstances in which troponin results may be misleading. Firstly, the trials which comprise the evidence base for the therapeutic effect were only based on patients with documented coronary artery disease. Secondly, troponin is elevated in patients with heart failure and concentrations fall with appropriate treatment. Thirdly, there is no internationally accepted standard for troponin, and there are therefore important differences at the 'cut-off' values between the methods of different manufacturers. Fourthly, immunoassays suffer from interfering antibodies and at least 17 case reports have been published outlining false positive tests. It is important that the shortfalls of troponin tests in the diagnosis of acute coronary syndromes are widely recognized.