Performance of a point-of-care qualitative triple cardiac marker screen under controlled laboratory conditions and in an emergency department setting

Background: The performance of point-of-care testing under controlled laboratory conditions may vary from results obtained in actual patient care settings. User errors are a major cause of this discrepancy. Methods: We studied the clinical performance of the Cardiac STATus (Spectral USA, Frederick, MD), a qualitative triple cardiac marker point-of-care test, under controlled laboratory conditions and in actual practice in an emergency department (ED) satellite laboratory. First-draw samples obtained from patients presenting to the hospital emergency department with chest pain were used for the study. Tests were performed in the chemistry research laboratory by a company product specialist or in an emergency department satellite laboratory by hospital staff. Test results were analyzed by correlation to the clinical discharge diagnosis. Results: In the emergency department, for the test system as a whole (any one or more marker(s) positive versus all three markers negative), sensitivity was 63%, specificity was 81%, positive predictive value was 26%, and negative predictive value was 95%. A manufacturer-supplied product specialist in a laboratory setting achieved very similar sensitivity, specificity, and positive and negative predictive values. Conclusions: The performance of this system under controlled laboratory conditions can be applied to estimate its performance at the point of care.