After review of thousands of troponin-I patient profiles and discussions with members of the Cardiology Department, the Laboratory revised the upper limit of normal troponin-I. Previous reference range of 0.00 to 0.04 ng/ml is changed to 0.00 to 0.14 ng/ml. No change is made in the 0.5 ng/ml cutoff indicative of myocardial infarction. The changed normal range will reduce the percentage of indeterminate troponin-I values from 28 percent to 7 percent. Our previous assay (first generation test) had an indeterminate rate of 4 percent to 5 percent. It is likely that the lower the troponin-I result, the better as far as long-term cardiac risk (LDL cholesterol, CRP or BNP). Very low level troponin-I values are not associated with an increased risk of myocardial infarction in the acute care setting unless the troponin-I levels are increasing significantly ( >0.10 ng/ml differences in sequential results).
|Old Troponin-I Range||0.00-0.04||0.05-0.49||>0.50|
|New Troponin-I Range||0.00-0.14||0.15-0.49||>0.50|