Why are the thresholds assay-specific?

High-sensitivity troponin assays from different manufacturers report different absolute numbers for the same patient, so the ESC publishes separate cut-offs for each. Roche hs-cTnT, Abbott hs-cTnI, and Siemens hs-cTnI all have their own rule-in, rule-out, and delta values, which is why you must select the right assay.

What does observe mean?

Observe is the middle zone where neither rule-in nor rule-out criteria are met. These patients need a further troponin measurement, usually at 3 hours, plus ongoing clinical and ECG assessment before a decision can be made.

Is a rule-out enough to discharge?

No. The algorithm rule-out is only valid alongside a non-ischaemic ECG and low clinical risk, and for the very-low single-value pathway, symptom onset more than three hours earlier. The biomarker is one part of a structured pathway, never the whole decision.

What units does this use?

Nanograms per litre, ng/L, which is numerically identical to picograms per millilitre, pg/mL. Make sure your laboratory reports in these units and not in micrograms per litre, which would be a thousand-fold different.

Does a positive troponin always mean a heart attack?

No. Troponin rises in many conditions including myocarditis, pulmonary embolism, sepsis, renal failure, and tachyarrhythmia. A dynamic rise raises the chance of acute myocardial infarction, but the diagnosis still depends on the clinical picture and ECG.

High-Sensitivity Troponin Serial Rise Calculator

High-sensitivity troponin assays let emergency clinicians rule acute coronary syndrome in or out within an hour using a baseline value and a single repeat. The decision hinges on assay-specific thresholds and on the change between the two samples. This calculator applies the published ESC algorithm rules so you can see the verdict and why it was reached.

How it works

The algorithms are deliberately ordered so that rule-in is checked before rule-out for safety. For the 0h/1h pathway the logic is:

rule-in   if baseline >= high  OR  1h delta >= delta_rule-in
rule-out  if baseline < very_low
          OR (baseline < low  AND  1h delta < delta_rule-out)
otherwise observe

The thresholds differ by assay. For Roche hs-cTnT the published values are a very-low of 5, a low of 12, a direct rule-in of 52 ng/L, and one-hour deltas of 3 and 5. Abbott and Siemens assays carry their own numbers, which the tool substitutes when you change the selection. The 0h/3h pathway instead compares both values against the 99th percentile upper reference limit and looks for a significant dynamic change.

Notes and cautions

A rule-out result is only valid with a non-ischaemic ECG and low clinical risk, and the single-sample very-low rule-out assumes symptom onset more than three hours earlier. A rule-in raises the probability of myocardial infarction but does not prove it, because troponin also rises in myocarditis, pulmonary embolism, sepsis, renal failure, and tachyarrhythmia. The cut-offs here are published educational values; always use your own laboratory’s validated thresholds and combine the result with the full clinical assessment.