11 Troponinemia
11.1 High-sensitivity Troponin
- Overcomes early “Troponin-blind” period
- General 99th percentile reference limit is 19 ng/L (pg/mL)
- Sex-specific 99th percentile cutoffs for hc-cTnI:
- females: 16 ng/L (pg/mL)
- males: 34 ng/L (pg/mL)
- Trend at q1/2/3 hr intervals (as opposed to q3-4h with standard Troponin)
- Trending q2h/q3h is more commonly seen
- UMich algorithm: if hs-cTnI increases by ≥ 6, then ACS ruled in
11.1.1 Caution
- Late presenters with low hs-cTn, ∆ may be small
- In other words, those presenting late may only have a small ∆ in their hs-cTn so don’t just rely on the ∆.
- Single sample rule out only if last chest pain > 6 hrs ago (and no recurrent pain)
- In other words, if pt presents and last CP episode was > 6 hrs ago + hs-cTnI is normal → ACS ruled out
11.3 Note Documentation
MI/ACS: “STEMI”, “NSTEMI”, “Unstable angina”
“Type 2 myocardial infarction”
“Myocardial injury due to _____”
