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Test Code HSTNI Troponin I, High Sensitivity, Plasma


Specimen Required


Collection Container/Tube:

Preferred: Mint green top (lithium heparin gel)

Acceptable: Green top (lithium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Plasma gel tube should be centrifuged within 2 hours of collection.

2. Green-top tube should be centrifuged, and the plasma aliquoted into a plastic vial within 2 hours of collection.


Forms

If not ordering electronically, complete, print, and send a Cardiovascular Test Request Form (T724) with the specimen.

Useful For

Excluding the diagnosis of acute coronary syndromes

 

Explaining troponin T elevations related to skeletal myopathy and/or assay interferences

Method Name

Electrochemiluminescence Immunoassay

Reporting Name

Troponin I, High Sensitivity, P

Specimen Type

Plasma

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Frozen (preferred) 180 days
  Refrigerated  48 hours
  Ambient  4 hours

Reject Due To

Gross hemolysis Reject

Clinical Information

Troponin is a complex that regulates the contraction of striated muscle. It consists of 3 subunits (C, T, and I) that are located periodically along the thin filament of the myofibrils. Troponin I inhibits actomyosin ATPase.

 

Troponin I is an inhibitory protein and exhibits in 3 isoforms: cardiac muscle, slow-twitch skeletal muscle, and fast-twitch skeletal muscle. The cardiac form of troponin I has 31 amino acid residues on its N-terminal, which allow for specific polyclonal and monoclonal antibody development, as they are not present in the skeletal forms. The cardiac specificity of this isoform improves the accuracy of diagnosis in patients with acute or chronic skeletal muscle injury and possible concomitant myocardial injury.

 

Troponin I is the only troponin isotope present in the myocardium and is not expressed during any developmental stage in skeletal muscle. Troponin I is released into the bloodstream within hours of the onset of symptoms of myocardial infarction or ischemic damage. It can be detected at 3 to 6 hours following onset of chest pain, with peak concentrations at 12 to 16 hours, and remains elevated for 5 to 9 days.

Reference Values

Males ≥18 years: ≤20 ng/L

Females ≥18 years: ≤15 ng/L

 

Reference values have not been established for patients younger than 18 years old.

Day(s) Performed

Monday, Wednesday, Friday

Report Available

2 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

84484