The lower limit of detection (LOD) is taken as 5ng/L
As the tests are becoming more sensitive, more false positives may be recorded
The diagnosis of AMI requires:
A ↑ and/or ↓ of biomarkers (e.g. cTnI) with at least one value above the 19/11 ng/L PLUS
Symptoms of ischaemia or appropriate ECG changes and/or imaging evidence of new wall motion abnormality
Troponin is only one variable. Risk stratification requires clinical assessment and /or scoring e.g. HEART
Two measurements of TnI are required (at presentation and after 3 hours) unless max pain (and no longer in pain) was > 3 hours ago (one <LOD will suffice in low risk patients)
AMI = rise above normal and Δ > 50% over that same period
Δ 20-100% within a 3 hr period requires further testing
Δ <20% within 3 hrs is not consistent with an acute event
Dx of AMI post PCI or CABG requires a three fold increase in TnI