Background: It is currently unknown, whether the uniform (universal clinical practice for more than two decades) or two sex-specific cut-off levels are preferable when using high-sensitivity cardiac troponin (hs-cTn) in the diagnosis of myocardial infarction (MI).

Aim: To improve the management of suspected MI in women by exploring sex-specific versus the uniform cutoff-levels for hs-cTnT.

Methods: In a prospective diagnostic multicenter study, 2734 adult patients (876 women and 1858 men) with suspected MI were enrolled at presentation to emergency department (ED). The final diagnosis was adjudicated by two independent cardiologists using all available information including serial hs-cTnT blood concentrations twice: once using the uniform 99th percentile cut-off value of 14 ng/L, and once using sex-specific 99th percentiles of hs-cTnT (women 9ng/L, men 15.5 ng/L). Duration of follow-up was 2 years.

Results: Using the uniform cut-off value, 14.5% (n=127) of women and 18.6% (n=346) of men received a final diagnosis of MI. Among these, at ED presentation levels of hs-cTnT were already above the uniform cut-off value in 91% of women and 91% of men (sensitivity 91%, specificity 79% in women and men; p=ns). After re-adjudication using sex-specific 99th percentiles, diagnostic reclassification regarding MI occurred in only 3 patients (0.1% of all patients and 0.6% of MI patients). Two women were upgraded from unstable angina to MI, while one man was downgraded from MI to unstable angina. All-cause mortality during follow-up was the primary prognostic endpoint. Similar to the diagnostic findings, only a very low number of patients (0.07% of all patients and 1.2% of deaths) were reclassified by the use of sex-specific versus uniform 99th percentiles in the prediction of death. These diagnostic and prognostic results were confirmed when using two alternative pairs of uniform/sex-specific cut-off values.

Conclusions: The uniform 99th percentile should remain the standard-of-care when using hs-cTnT for the diagnosis of MI.