Usage of troponin in the real world: a lesson for the introduction of biochemical assays

Background: Studies have demonstrated economic and clinical effectiveness using troponin as a risk stratification tool in chest pain patients. Those with a positive result are investigated invasively, whilst those with a negative result and ECG are promptly mobilized, facilitating discharge. Aim: To determine whether our use of troponin I (cTnI) in routine clinical practice conforms to ideal standards. Design: Audit study. Methods: Data were collected from 93 laboratory request forms for cTnI measurement on 72 patients with matched available patient records. Results: Eighty requests had no information regarding timing of blood sample in relation to the clinical event; 39% gave no clinical indication. Only 71% of results were available within 12 h. An admission diagnosis of acute coronary syndrome (ACS) was made in 25%. Fifteen had typical cardiac chest pain with a negative cTnI: 6 of these had an exercise treadmill test before discharge. Nine had a positive cTnI, but only two had coronary angiography. Of patients with negative cTnI and possible ACS, 84% were in hospital for >4 days. Discussion: The introduction of troponin assays into widespread use requires careful assessment. cTnI requests and subsequent patient management remain below expected standards. Ideally, the laboratory should provide an accurate result within a reasonable time frame, while physicians need to request cTnI at a suitable time-point and use the result appropriately. Lessons from the introduction of cTnI measurement may be useful for the introduction of future new tests in other areas of cardiology and medicine.