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Reference Notes and Guidelines

The high sensitive cardiac Troponin I assay (hs-cTnI) expedites the exclusion of non-ST segment elevation acute coronary syndrome (NSTE-ACS) in individuals with acute chest pain. To establish the correct diagnosis, all cTn results must be interpreted in the context of risk assessment scores (GRACE, TIMI) and clinical history, physical examination, ECG and other markers. Based on significant elevations observed in serial testing at e.g. 3 , 6-hour or longer after baseline as well as the clinical assessment, algorithms can be developed to rule- out/rule-in acute myocardial infarction. Grossly abnormal values (10x 99%ile) together with clinical presentation would indicate the need for coronary intervention. However, baseline and re-testing at levels below the assayOs lower limit of detection (LOD, 3.2 ng/L) has a relatively high negative predictive value (NPV).

Due to the high tissue specificity of cTnI in cardiac and skeletal muscles, elevated values may also be found in structural heart diseases and chronic cardiac conditions (heart failure, myocarditis, arrhythmias), as well as renal failure, chronic renal disease, pulmonary embolism, or conditions involving skeletal muscle injury resulting from surgery, trauma, extensive exercise or muscular disease. As the upper reference limit is set at 99th percentile, the negative predictive value of retested hs-cTnI serial draws after the onset of the pain has been determined to be ≧ 99%.

Sources:

1. AHA/ACC Guideline for the Management of Patients With Non-ST-Elevation Acute Coronary Syndromes. Journal of the American College of Cardiology. December 23, 2014, Vol. 64, No. 24

2. Sawaya H, Sebag IA, Plana JC, et al. Early Detection and Prediction of Cardiotoxicity in Chemotherapy-Treated Patients. The American journal of cardiology 2011;107(9):1375 1380. doi:10.1016 j.amjcard.2011.01.006.

3. VIDAS High sensitive Troponin I reagent kit insert. BioMerieux; 9309099A-en-2015/10.