II. Indications

III. Protocol: Typical

  1. Troponin I every 4 to 6 hours for 3 samples
  2. Trend upward above discriminatory Troponin I values suggests acute Myocardial Infarction

IV. Protocol: Troponin and CK-MB with 2 hour intervals

  1. Initial tests at presentation
    1. Troponin I or Ultrasensensitive Troponin T
    2. CK and CK-MB
  2. Tests at 2-4 hours after initial labs
    1. Troponin I
    2. CK and CK-MB
  3. Interpretation: Case in which acute Myocardial Infarction unlikely
    1. Initial Ultrasensitive Troponin T negative or
    2. Second Troponin I negative and CK-MB not increasing
  4. References
    1. Weingart in Majoewsky (2012) EM:RAP 12(4): 6-7

V. Protocol: Troponin and CK-MB every 8 hours for 3 samples (older protocol)

  1. Protocol
    1. Obtain Troponin at 0 hours, 8 hours and 16 hours
      1. Primary Cardiac Marker: Specific for cardiac event
      2. Not useful for monitoring event extension
        1. Levels stay elevated for 14 days
    2. Obtain CK-MB at 0 hours, 8 hours, and 16 hours
      1. Primary purpose: Follow cardiac event extension
      2. Decreases more rapidly than Troponin after event
  2. Test Sensitivity of combined protocol
    1. Test Sensitivity: >98% at 8 hours
    2. Test Specificity: 80 to 95% at 8 hours
  3. References
    1. Jernberg (2000) Am J Cardiol 86:1367-71 [PubMed]

VI. Labs: Troponin

  1. Rises: 3-6 hours
  2. Peaks: 20 hours
  3. Duration: 14 days
  4. Subunits
    1. Troponin T
    2. Troponin I

VII. Labs: Creatine Phosphokinase (CPK)

  1. Rises: 4-6 hours
  2. Peaks: 12-24 hours
  3. Duration: 4-5 days
  4. Subunits (Fractionate to CK-MB only if CPK increased)
    1. CK-MB Fraction (duration for 2-3 days)
    2. CK-MB over 5% of total CPK suggests Myocardial Injury

VIII. Labs: Myoglobin

  1. Advantage: First Cardiac Marker to increase
  2. Disadvantage: Poor Specificity (only helps if negative)
  3. Rises: 1-2 hours
  4. Peaks: 4-6 hours
  5. Duration: 1-2 days

IX. Labs: Glutamic oxaloacetic transaminase (AST, SGOT)

  1. Peaks: 24-36 hours
  2. Duration: 5 days

X. Labs: Lactic Dehydrogenase (LDH)

  1. Peaks: 24-48 hours
  2. Duration: 14 days

XI. Labs: White Blood Cell Count

  1. Predicts adverse events in Unstable Angina
  2. Morbidity and mortality increase with increased WBCs
    1. WBC Count >10,000: High risk of adverse event
    2. WBC Count >15,000: Very high risk of adverse event
  3. References
    1. Cannon (2001) Am J Cardiol 87:636-9 [PubMed]

Images: Related links to external sites (from Bing)

Related Studies (from Trip Database) Open in New Window

Ontology: Cardiac markers (C1271630)

Concepts Laboratory Procedure (T059)
SnomedCT 390319003, 389587001, 391485008
English cardiac markers, cardiac marker, Cardiac markers (procedure), Cardiac markers
Spanish determinación de marcadores cardíacos (procedimiento), determinación de marcadores cardíacos