Aims: To evaluate the diagnostic performance of a portable semi-quantitative whole blood immunoassay measuring soluble human fatty acid-binding protein [H-FABP] (CardioDetect) for the pre-hospital detection of myocardial infarction (MI).
Methods and results: We enrolled prospectively 108 consecutive patients with acute ischemic type chest pain in whom the first medical care was delivered by a mobile intensive care unit (MICU). CTnI, myoglobin, CK-MB and CardioDetect were first assessed in the MICU before hospital admission using point-of-care assays and then cTnI was serially measured during the hospital stay. MI was defined as a positive cTnI in any sample over the first 24 h. The vast majority of the patients (77/108) were admitted <3 h of symptoms onset. Pre-hospital cTnI sample was normal in 96 patients (88.9%) of whom 43 had subsequent cTnI elevation. A positive H-FABP using the CardioDetect assay had a significantly better sensitivity than cTnI, myoglobin and CK-MB (87.3% vs 21.8%, 64.2% and 41.5%, respectively) to identify MI. The significant better sensitivity of the CardioDetect assay was also observed among patients who presented <3 h of symptom onset. The specificity of the CardioDetect assay was significantly better than that of myoglobin, irrespective of the time delay from symptom onset to measurement. In patients with normal pre-hospital cTnI and no ST-elevation (n=63), assessment based only on a positive H-FABP had 83.3% sensitivity, 93.3% specificity for the diagnosis of an evolving MI.
Conclusion: Early assessment of H-FABP in patients presenting with chest pain improves the diagnosis of ongoing MI.