Human heart-type fatty-acid-binding protein as a point-of-care test in the early diagnosis of acute myocardial infarction

Background: At very early stages of acute myocardial infarction (AMI), highly sensitive biomarkers are still lacking. Aim: To evaluate the utility of human heart-type fatty acid-binding protein (h-FABP) for early diagnosis of AMI. Design: Prospective diagnostic study. Methods: Consecutive patients presenting to the emergency department with chest pain or dyspnoea within 24 h of symptom onset were included. At presentation, the h-FABP test result was compared to the standard diagnostic work-up, including repeated ECG and troponin T measurements. Sensitivity analysis was performed for inconclusive tests. Results: We enrolled 280 patients presenting to hospital with a median symptom onset of 3 h (IQR 2-6 h): 109 (39%) had AMI. At presentation, h-FABP had a sensitivity of 69% (95%CI 59-77) and specificity of 74% (95%CI 66-80); 45 tests were false-positive and 34 were false-negative. Omitting inconclusive tests increased sensitivity and specificity only slightly. AMI was identified significantly earlier by h-FABP than by troponin T (24 vs. 8 patients, p = 0.005). Discussion: Although h-FABP can help to detect myocardial damage at an early stage in patients with chest pain or dyspnoea, it appears unsuitable as a stand-alone test for ruling out AMI.