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Test Code TNI Troponin I

Additional Codes

Cerner

NextGen

Troponin I

Troponin I

Methodology

(Vitros) Immunometric immunoassay, Chemiluminescent

Patient Preparation

None

Collection Instructions

  • Standard phlebotomy practices.
  • Troponin testing is normally performed in the following order
    • 0 hr (Baseline)
    • 3 hr (delta calculated)
    • 6 hr (delta calculated)

Specimen Requirements

Container

Specimen Type

Tube

Lithium Heparin Plasma

PST

 or  or 

Stability

Storage

Temperature

Stability

Room Temperature

18-28°C

Not recommended (less than 2 hours)

Refrigerated

 2-8°C

≤ 7 days

Frozen

≤-20 °C

4 weeks

Thaw 1 time only

Rejection Criteria

Gross Hemolysis

Turbid Specimens

Result Reporting and Reference Values

Reported in ng/mL

Negative

0.00-0.034

Borderline

0.035-0.119

Consistent with MI (Critical Value)

≥ 0.120

Reflex Testing

None

Limitations

  • Ortho reports a bias with the following:
    • Biotin can cause a negative bias.
  • Ortho reports no significant effect with the following:
    • Bilirubin up to 20 mg/dL

Useful For

Troponin I (TNI) is a protein normally found in muscle tissue that, in conjunction with Troponin T and Troponin C, regulates the calcium dependent interaction of actin and myosin. Clinical studies have demonstrated that cardiac Troponin I (cTnI) is detectable in the bloodstream 4-6 hours after an acute myocardial infarction and remains elevated several days thereafter. Thus, cTnI elevation covers the diagnostic windows of both CK-MB and LDH. Further studies have indicated that cTnI has a higher clinical specificity for myocardial injury than does CK-MB. Because of its cardiac specificity and sensitivity, cTnI has been used as a reliable marker in evaluating patients with unstable angina and non-ST segment elevation acute coronary syndrome.

Other conditions resulting in myocardial cell damage can contribute to elevated cTnI levels; these conditions include sepsis, congestive heart failure, hypertension with left ventricular hypertrophy, hemodynamic compromise, and myocarditis, mechanical injury including cardiac surgery, defibrillation and cardiac toxins such as anthracyclines.