Diagnostic accuracy of quantitative heart-fatty acid binding protein assays compared with Cardiodetect ® in the early detection of acute coronary syndrome

Abstract

Heart-fatty acid binding protein (h-FABP) has been proposed as a cardiac marker for the early detection of acute coronary syndrome (ACS). In a study of 677 patients admitted to the emergency department (ED) for chest pain, we found that a semiquantitative point-of-care test that detects h-FABP (Cardiodetect(®)) had low sensitivity for the prediction of ACS. The aim of this ancillary study was to analyze and compare the performance of h-FABP for early ACS diagnosis in this large cohort of unselected patients, using a quantitative immunoassay and Cardiodetect(®). h-FABP was measured with a ready-to-use, solid-phase, enzyme-linked immunosorbent assay (ELISA) in 677 patients admitted to the ED with chest pain and suspected non-ST-segment elevation ACS. Two physicians, blinded to the results of the marker, categorized patients as having or not having non-ST-segment elevation ACS. Non-ST-segment elevation ACS was diagnosed in 185 patients (27.3%). The median h-FABP level was higher in patients with ACS (1.36μg/L, interquartile range [IQR] 0.59-3.55) than in those without ACS (0.58μg/L, IQR 0.24-1.34; P<0.01). The area under the curve was 0.68 (95% confidence interval [CI] 0.63-0.73). h-FABP did not improve the performance of a model that included the usual diagnostic tools for ACS management (odds ratio 0.92, 95% CI 0.32-2.70). The classification agreement between the ELISA and Cardiodetect(®) was 92.1% (kappa 0.39). In this study, we confirmed that measurement of h-FABP was insufficient to be used as a marker of ACS and NSTEMI in ED, whatever the analytical technique used.