Clinical performance of a new point-of-care cardiac troponin I assay compared to three laboratory troponin assays.

Background: Studies of cardiac markers in diagnosing acute myocardial infarction (AMI) have mostly been performed using central laboratory platforms. The AQT90 FLEX TnI (troponin I) assay is designed for quantitative point of care testing (POCT). This study evaluated clinical performance in diagnosing AMI of the AQT90 FLEX TnI POCT assay compared with central laboratory troponin assays.

Methods: The study included 458 chest pain patients. Blood samples were obtained on admission and after 6-9h. Blood was analyzed using the following assays: AQT90 FLEX TnI, Access AccuTnI, Abbott AxSYM ADV, Roche cTnT, Roche CKMBmass. Patients were diagnosed with AMI according to the new universal definition of AMI.

Results: The performance of the AQT90 FLEX TnI assay on admission was equivalent to the Abbott AxSYM ADV cTnI but inferior to the AccuTnI. After 6-9 h both laboratory based assays were superior. The AQT90 FLEX TnI had a negative predictive value (NPV) of 90 and 96% (admission; 6-9 h). No statistical differences were seen in receiver operating characteristics analysis.

Conclusions: The AQT90 FLEX TnI POCT assay was marginally inferior to the two laboratory based assays of cTnI in diagnosing AMI. A high (NPV) may make this assay suitable as a rule out marker.