Troponin is the standard, rising at 3 to 6 hours and remaining raised for days
Expansion
| Marker | Rises | Peaks | Normalises |
|---|---|---|---|
| Troponin I and T | 3 to 6 h | 24 h | 7 to 10 days |
| High sensitivity troponin | 1 to 3 h | ||
| CK-MB | 4 to 6 h | 24 h | 2 to 3 days |
| Myoglobin | 1 to 2 h | 6 h | 24 h |
Troponin is highly cardiac specific but not specific to infarction. It is raised in any cause of myocardial injury: myocarditis, pulmonary embolism, sepsis, heart failure, arrhythmia, chronic kidney disease, and after cardiac procedures.
The diagnosis of myocardial infarction therefore requires a rise and fall in troponin with at least one value above the 99th centile, plus clinical, ECG or imaging evidence of ischaemia. This is why serial sampling matters more than a single value.
High sensitivity assays allow rapid rule-out pathways at 0 and 1 or 0 and 3 hours, using both the absolute value and the delta between samples.
CK-MB retains a niche for detecting reinfarction, since its faster normalisation means a second rise is interpretable.