Background: At present, measurements of troponins play a key role in the diagnosis of myocardial infarction. There is a consensus that a turnaround time (TAT) of 1 h or less should be achieved for cardiac marker assays. However, little is known about the real delays between the patient's arrival at the emergency department (ED) and the reporting of the test.
Methods: In the present study, the TATs of a cardiac marker, troponin T (TnT), were analyzed at a central laboratory at Kuopio University Hospital in a population consisting of 215 patients who were admitted to the hospital ED. Four specific time points were recorded: 1) the time of the patient's arrival to the ED, 2) the time of the ordering of the test, 3) the time when blood samples arrived at the laboratory, and 4) the time of completion and reporting of the test.
Results: The median diagnostic TAT from patient's arrival to the reporting of the TnT result was 122 min. The clinical median TAT was 46 min and the laboratory median TAT was 69 min. Laboratory TAT consisted of the preanalytical TAT at the ED (median 14 min), pre- and postanalytical TAT in the laboratory (median 40 min), and the analytical TAT (on average 10 min). The laboratory TAT was approximately half of the complete diagnostic TAT.
Conclusions: On the basis of this analysis, we propose new concepts for the TATs in the diagnostic process: diagnostic TAT which consists of clinical and laboratory TAT. The focus should be shifted from the analytical TAT to the diagnostic process as a whole.