High-Sensitivity Troponin

High-sensitivity troponin (hsTn) assays are now available from several vendors. There are now hundreds of clinically-relevant studies published on these newer assays. These assays should not be confused with the standard troponin assays that are still widely used. The newer hsTn assays are over ten times more sensitive than the traditional troponin assays.

The term “high sensitivity” reflects these newer assay's lower limits of detection, it does not refer to a difference in the form of cardiac troponin being measured—these assays measure the same troponin molecule. The term "high-sensitivity" can be used to describe a troponin assay that has:

These new high-sensitivity troponin assays have ten times the sensitivity of other cTnI and cTnT assays. Instead of having lower limits of detection around 0.01 ng/L, the new assays can detect down to 0.001 ng/L. Having this increased sensitivity means we will be able to detect smaller changes sooner. In patients with MI, levels of cTn can rise rapidly and be detected within 1 hour when using high-sensitivity assays.³ This will increase our sensitivity for cardiac damage. Indeed, studies are showing that we can detect cardiac issues before frank ischemia and necrosis even occur. Studies are showing that the hsTn assays can be used to assess cardiac prognosis and even pre-cardiac event risk.

However, this increased sensitivity comes at a price—the clinical specificity will decrease. If we can now detect troponin in seemingly healthy patients, we will no longer be able to think of troponin as a qualitative ACS/AMI cut-off marker. The paradigm of thinking that "troponin is present when a person has dying heart tissue" needs to be revamped. These new assays are revealing that troponin is detectable in many patients, some of whom seem healthy. Thus, we will need new criteria and stricter reference ranges that help us hone in on true ischemia and infarcts. Clinicians will need to become familiar with using hsTn on a much wider quantitative scale, across a larger spectrum of patients, from patients with frank AMI to those with subclinical, mild 'pre-ischemia' who are only at risk for AMI.