Cardiac Biomarkers: Troponin Trends, BNP Pitfalls, and the Chronic Elevation Problem
Cardiac Biomarkers: Troponin Trends, BNP Pitfalls, and the Chronic Elevation Problem High-sensitivity troponin changed everything. BNP is falsely low in obesity. And a single troponin is almost never enough. Troponin: The Myocardial Injury Marker High-Sensitivity Troponin (hs-cTn) High-sensitivity troponin assays detect far lower concentrations than older assays, enabling faster rule-out of MI but also detecting chronic low-level myocardial injury that was previously invisible. This has created a new problem: chronic troponin elevation without acute MI . The Trend Is Everything A single troponin value is not diagnostic. Acute MI shows a rise-and-fall pattern —troponin increases >20% from baseline over 3–6 hours. Chronic elevations (stable, flat values on serial testing) indicate non-ACS myocardial stress. Always order serial troponins at 0 and 3 hours (some protocols use 0 and 1 hour for rapid rule-out with hs-cTn). A flat troponin at two time points effectively ru...