Rapid immunoassays provide concentration levels of cTnI and cTnT that are approximately 96% sensitive and 94% specific for cardiac injury.
Each diagnostic company develops their unique antibody against epitopes on the proteins. There is only one assay available for cTnT. However, there are several different antibodies that are used by manufacturers to detect cTnI. Consequently, different assay methods may not correlate well. Standardization is needed for intra-laboratory comparisons.
Reference Ranges for an adult:
cTnT <0.01 ng/mL No cardiac injury
cTnI references may vary with different assay methods, but approximate these values:
- Equal to or < 0.03 ng/mL -- No detectable cardiac injury
- 0.04-0.49 ng/mL -- Cardiac muscle injury
- Equal to or > 0.5 ng/mL-- Myocardial infarction
