Cardiac troponin I (cTnI) is a protein that shows up in the blood when heart muscle cells are damaged. It's used in an alternative cardiac staging system alongside brain natriuretic peptide (BNP), typically when NT-proBNP testing isn't available.
The normal cutoff for cTnI is less than 0.1 nanograms per milliliter. Here's Show Full Answer
Cardiac troponin I (cTnI) is a protein that shows up in the blood when heart muscle cells are damaged. It's used in an alternative cardiac staging system alongside brain natriuretic peptide (BNP), typically when NT-proBNP testing isn't available.
The normal cutoff for cTnI is less than 0.1 nanograms per milliliter. Here's how the staging breaks down based on cTnI and BNP levels:
- Stage 1 — Both BNP and cTnI are within normal range
- Stage 2 — Either BNP or cTnI is elevated
- Stage 3 — Both BNP and cTnI are elevated
- Stage 3B — BNP is very high (700 picograms per milliliter or more) and cTnI is also elevated
Higher stages generally indicate more serious heart involvement and are associated with a shorter life expectancy. Stage 3B in particular tends to have a more serious outlook.
It's always worth discussing your specific biomarker results with your care team, as they can give the most accurate picture of what the numbers mean for your individual situation.
June 7