Troponin I (hs)
What it measures, and what changes the number.
Troponin I is a protein found in heart muscle cells, where it helps control contraction. When heart muscle cells are damaged, troponin I is released into the blood. The high-sensitivity (hs) version of the test can detect very small amounts.
It is often measured together with other cardiac markers such as NT-proBNP and CK-MB, and results are usually compared across repeated samples taken some hours apart, because the change over time is part of how the test is read.
Different manufacturers' troponin I assays are not standardised against each other, so results from different labs or methods cannot be compared directly, and some use sex-specific cut-offs. Strenuous exercise and kidney function can also influence the level. Labs may report it as Troponina I alta sensibilidad (hs-cTnI).
Often read alongside: NT-proBNP, CK-MB, CK, Creatinine