Author Affiliations: Departments of Cardiology and Internal Medicine, University Hospital Basel, Basel, Switzerland (Drs Reichlin and Mueller); and Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts (Dr Reichlin).
We thank Kavsak and Carlton and colleagues for taking interest in our article.1
The points raised by Kavsak give us the opportunity to clarify 2 important details that might have lead to misunderstandings. First, the algorithm (including the values for absolutes changes used) was derived and validated data driven.1 This approach is in contrast to the theoretical considerations and their extrapolations described by Kavsak. Second, the best cut-off levels for specific diagnostic decisions such as the rule-out or the rule-in of acute myocardial infarction (AMI) using high-sensitivity cardiac troponin T (hs-cTnT) often differ from the 99th percentile, a level defined to differentiate normal levels from elevated levels. The algorithm aims to best separate patients with AMI from patients with other causes of chest pain, that might also have minor hs-cTnT elevations for various reasons. It is therefore not surprising that the best cut-off value for hs-cTnT to rule-in AMI is higher than the 99th percentile. A large multicenter study designed for external validation of our results is currently enrolling patients. We agree with Kavsak and Carlton and colleagues that the 3-hour algorithm suggested by the European Society of Cardiology (ESC) guidelines should be followed until these results become available.
Reichlin T, Mueller C. Testing Times: We Are Still Some Way From Getting the Best Out of Sensitive Troponin Assays—Reply. JAMA Intern Med. 2013;173(6):477-478. doi:10.1001/jamainternmed.2013.2787