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Accurate diagnosis of cardiac emergencies is a critical responsibility of emergency physicians. The extensive differential diagnosis of chest pain must be narrowed rapidly and accurately to enable timely, lifesaving interventions.[1] In addition to the history and physical examination, several diagnostic modalities assist in distinguishing among potential causes of chest pain.[2] Measurement of cardiac troponins (cTns) has become an integral component of cardiac evaluation and diagnosis.[3] CTns were introduced for clinical application in 1995 following the approval of the first cTn T (cTnT) assay.[4] Subsequent advances in assay design demonstrated that enhanced cardiac specificity and markedly improved sensitivity increased the diagnostic accuracy and frequency of cardiovascular disease detection, particularly with the development of high-sensitivity cardiac troponin (hs-cTn) assays.[5] Progressive refinement of troponin assays has significantly improved the speed and precision of acute myocardial infarction (AMI) detection. Fourth-generation assays identified substantial myocardial injury but exhibited limited early sensitivity. High-sensitivity 5th-generation assays enabled the detection of minute troponin concentrations at single-digit nanogram-per-liter levels, facilitating earlier diagnosis and enabling accelerated rule-out protocols. However, increased analytical sensitivity resulted in measurable elevations in nonischemic conditions such as chronic kidney disease (CKD) and heart failure. Sixth-generation assays demonstrate further improvements in analytical precision and reproducibility, enhancing differentiation between acute ischemia and other etiologies of troponin elevation and optimizing timely clinical decision-making in emergency care.

Myocardial infarction results from obstruction of coronary blood flow, producing ischemia within the myocardium supplied by the affected vessel.[16] The ensuing imbalance between oxygen supply and myocardial oxygen demand leads to cellular hypoxia, necrosis, and myocyte death.[17] Disruption of cell membrane integrity during this process releases intracellular constituents into the interstitial space, which subsequently enter the systemic circulation.[18] These constituents, including cTns, become detectable in serum when released in sufficient quantity. A basal concentration of troponin is present in the circulation of healthy individuals due to normal myocyte turnover.[19] Elevated troponin levels indicate pathologic myocardial injury when the measured value exceeds the 99th percentile of the reference population, approximately 3 standard deviations above the mean.[20] According to the Fourth Universal Definition of Myocardial Infarction, myocardial injury is defined by a cTn concentration above the 99th percentile upper reference limit (URL), characterized as acute when serial measurements demonstrate a rise, fall, or rise-and-fall pattern.[21] Serum troponin concentrations typically rise within 2 to 3 hours after the onset of ischemic chest pain, reach peak between 12 and 48 hours, and gradually return to baseline within 4 to 10 days.[22] The characteristic temporal rise-and-fall pattern helps differentiate myocardial infarction from other causes of troponin elevation.[23] The intrinsic plasma half-life of both cTnI and cTnT is approximately 2 hours. However, continued release from necrotic myocardium yields an apparent half-life of approximately 24 hours, whereas cTnT shows a slightly longer duration.[24] CTnT and cTnI possess amino acid sequences distinct from those of skeletal muscle isoforms and are encoded by separate genes.[25] Human cTnI contains an additional 31 amino acid residues at the amino terminus compared with skeletal muscle troponin I, conferring complete cardiac specificity.[26] Only 1 isoform of cTnI has been identified, and cTnI expression does not occur in healthy, regenerating, or diseased skeletal muscle of humans or animals.[27] CTnT is encoded by a distinct gene from that of skeletal muscle troponin T and contains an additional 11 amino-terminal residues that confer cardiac specificity.

CTnT and cTnI possess amino acid sequences distinct from those of skeletal muscle isoforms and are encoded by separate genes.[25] Human cTnI contains an additional 31 amino acid residues at the amino terminus compared with skeletal muscle troponin I, conferring complete cardiac specificity.[26] Only 1 isoform of cTnI has been identified, and cTnI expression does not occur in healthy, regenerating, or diseased skeletal muscle of humans or animals.[27] CTnT is encoded by a distinct gene from that of skeletal muscle troponin T and contains an additional 11 amino-terminal residues that confer cardiac specificity. Expression of cTnT isoforms in skeletal muscle has been documented in patients with muscular dystrophy, polymyositis, dermatomyositis, and end-stage renal disease.[28] For this reason, antibody selection in cTnT assay design requires careful optimization to prevent detection of noncardiac isoforms or immunoreactive proteins expressed in neuromuscular disorders, which may produce false-positive cTnT results unrelated to myocardial injury.[29]

The interpretation and management of elevated cTn levels require close collaboration among healthcare professionals to ensure timely diagnosis, appropriate treatment, and patient safety. Physicians, advanced practitioners, nurses, pharmacists, and laboratory staff each play a critical role in delivering coordinated, patient-centered care. Physicians and advanced practitioners are responsible for clinical assessment, integrating troponin results with patient history, ECG findings, and imaging studies to differentiate AMI from nonischemic causes, including CKD, sepsis, and myocarditis. The care team must apply evidence-based guidelines to prevent overdiagnosis and avoid unnecessary interventions while ensuring that acute coronary syndromes are managed promptly. All healthcare personnel, including advanced practice providers, should be knowledgeable about biomarkers of myocardial infarction. Nevertheless, history and physical examination remain indispensable.[112] Definitive confirmation of AMI requires additional evaluation, including ECG, echocardiography, and chest radiography. Reliance on a single serum assay is insufficient due to the potential for false-positive and false-negative results.[113] Nurses play a critical role in the early recognition of symptoms indicative of myocardial ischemia, accurate specimen collection and labeling, and monitoring for complications, including arrhythmias and progression of chest pain. The responsibilities of these healthcare personnel also include maintaining precise communication with the laboratory and medical teams regarding specimen timing, given the importance of troponin kinetics in serial testing protocols. Clinical laboratory professionals ensure the analytical accuracy and reliability of troponin assays by verifying quality control, minimizing preanalytical errors, and flagging results that require clinical interpretation. Pharmacists contribute by reviewing concomitant medications, managing anticoagulant and antiplatelet therapies, and preventing drug interactions that may exacerbate myocardial injury or affect the accuracy of cardiac testing.

Clinical laboratory professionals ensure the analytical accuracy and reliability of troponin assays by verifying quality control, minimizing preanalytical errors, and flagging results that require clinical interpretation. Pharmacists contribute by reviewing concomitant medications, managing anticoagulant and antiplatelet therapies, and preventing drug interactions that may exacerbate myocardial injury or affect the accuracy of cardiac testing. Ethical practice and precise communication are essential in managing elevated troponin results. Team members must review findings collaboratively to prevent overdiagnosis, unnecessary procedures, or patient distress. Interprofessional discussions, joint rounds, and thorough electronic health record documentation ensure that all members of the care team share a consistent understanding of the patient’s condition and treatment plan. Coordinated collaboration enhances diagnostic accuracy, reduces unnecessary testing, and improves patient outcomes. Through mutual respect, effective communication, and shared responsibility, the healthcare team can manage elevated troponin levels efficiently while maintaining optimal standards of patient safety and care quality.