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Test Code 408 Troponin I

Important Note

Human anti-mouse antibodies (hama) may be present in samples from patients who have received immunotherapy or diagnostic procedures utilizing monoclonal antibodies or in individuals who have been regularly exposed to animals. Additionally, other heterophile antibodies, such as human anti-goat antibodies may be present in patient samples. Manufacturers formulate assays to minimize the effects of these antibodies; however careful evaluation of patient results must be done when patients are known to have such antibodies.

Additional Codes

ALAB: TROP

PowerChart: Troponin I

MA Cerner: Cardiac Troponin I.

Test Method

DxI: Two-Site Immunoenzymatic ("Sandwich") Assay; Beckman

iSTAT: Enzyme-Linked Immunosorbent Assay (ELISA); iSTAT

Specimen Requirement

Lithium heparin plasma.

Additional Specimen Collection Information

Collect blood in a lithium heparin (green-top tube). Filter the specimen and transfer plasma to a 2 mL or 0.5 mL sample cup for analysis. Care must be taken not to re-suspend cellular material. Hemolysis - No significant interference. Lipemic (> 3+) specimens must be ultracentrifuged prior to analysis. Icterus - No significant interference.

Specimen storage and stability:

  • Specimens should be separated from the cells within 2 hours of collection. Specimens may be at room temperature for up to 2 hours. After 2 hours specimens may be stored at 2-8°C for  up to 24 hours.
  • If specimens are to be stored longer than 24 hours they must be stored frozen at -20°C or lower. Frozen specimens should be thawed only once at room temperature. Do not thaw in a waterbath. Thawed samples must be centrifuged for 5 minutes at 2200 RCF prior to analysis. Frozen specimens are stable for 6 months.

Performance

Testing is performed Monday through Sunday.

Routine: Typically completed within 4 hours after the specimen arrives at the testing site.

STAT: Typically completed within 50 minutes after the specimen arrives at the testing site.

Reference Values

Troponin I: 0.00-0.04 ng/mL (Normal)

  • > 0.04-0.50 ng/mL  small myocardial injury possible.
    In patients with acute coronary syndrome, there is a higher risk for subsequent cardiac event.
  • > 0.50 ng/mL limit for acute mi. Remains elevated 4-9 days.        
    Serial determination of Troponin I provide the best data for clinical decision.

Post myocardial infarction, cardiac Troponin I levels are detectable 3-6 hours after onset of chest pain and peak at approximately 12-16 hours. Levels can remain elevated 4-9 days after acute myocardial infarction.           

CPT Code Information

84484 Chemistry: Troponin, quantitative

Useful For

Troponin I: Exclusion diagnosis of acute myocardial infarction

LOINC Code Information

10839-9 Troponin I.Cardiac [Mass/Volume] In Serum Or Plasma