Rationale and Comments

Unlike creatine kinase MB and myoglobin, the release of troponin I or T is specific to cardiac injury. Troponin is released before creatine kinase MB and appears in the blood as early as, if not earlier than, myoglobin after acute myocardial infarction. Approximately 30% of patients experiencing chest discomfort at rest with a normal creatine kinase MB will be diagnosed with acute myocardial infarction when evaluated using troponins. Single-point troponin measurements equate to infarct size for the determination of the acute myocardial infarction severity. Accordingly, there is much support for relying solely on troponin and discontinuing the use of creatine kinase MB and other markers.

Sponsoring Organizations

• American Society for Clinical Pathology

Sources

• Expert consensus

Disciplines

• Cardiovascular

References

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• Macrae AR, Kavsak PA, Lustig V, Bhargava R, Vandersluis R, Palomaki GE, Yerna MJ, Jaffe AS. Assessing the requirement for the 6-hour interval between specimens in the American Heart Association Classification of Myocardial Infarction in Epidemiology and Clinical Research Studies. Clin Chem. 2006;52(5):812-8.
  
• Kavsak PA, Macrae AR, Newman AM, Lustig V, Palomaki GE, Ko DT, Tu JV, Jaffe AS. Effects of contemporary troponin assay sensitivity on the utility of the early markers myoglobin and CKMB isoforms in evaluating patients with possible acute myocardial infarction. Clin Chem Acta. 2007;380(1-2):213-6.
  
• Saenger AK, Jaffe AS. Requiem for a heavyweight: the demise of the creatine kinase-MB. Circulation. 2008;118(21):2200-6.
  
• Reichlin T. Hochholzer W, Bassetti S, Steuer S, Stelzig C, Hartwiger S, Biedert S, Schaub N, Buerge C, Potocki M, Noveanu M, Breidthardt T, Twerenbold R, Winkler K, Bingisser R, Mueller C. Early diagnosis of myocardial infarction with sensitive cardiac troponin assays. N Engl J Med. 2009;361(9):858-67.