What is the cutoff value for high-sensitivity troponin (hs-troponin) for diagnosing acute Myocardial Infarction (MI) or Non-ST-Elevation Myocardial Infarction (NSTEMI)?

High-Sensitivity Troponin Cutoff Values for Diagnosing Acute MI/NSTEMI

For diagnosing acute myocardial infarction or NSTEMI, the cutoff for high-sensitivity troponin is the 99th percentile of the upper reference level, with specific values varying by assay type, and requires evidence of a rising and/or falling pattern. 1

Diagnostic Criteria for Acute MI/NSTEMI Using hs-Troponin

Primary Diagnostic Threshold

• The 99th percentile of the upper reference level is the established cutoff for considering myocardial necrosis 1
• This threshold varies by specific assay and manufacturer
• For diagnosis, both threshold and pattern are required:
  • At least one value above the 99th percentile
  • Evidence of a rising and/or falling pattern of troponin values

Assay-Specific Cutoff Values

High-sensitivity troponin assays have different cutoff values based on manufacturer:

Assay	Very Low (Rule-out)	99th Percentile	High (Rule-in)
hs-cTn T (Elecsys; Roche)	<5 ng/L	<12 ng/L	≥52 ng/L
hs-cTn I (Architect; Abbott)	<4 ng/L	<5 ng/L	≥64 ng/L
hs-cTn I (Centaur; Siemens)	<3 ng/L	<6 ng/L	≥120 ng/L
hs-cTn I (Access; Beckman)	<4 ng/L	<5 ng/L	≥50 ng/L

1

Serial Change Requirements

For accurate diagnosis, the pattern of change is crucial:

1. For initially elevated values (above 99th percentile):

   • A serial increase or decrease ≥20% is required 1

2. For values below or near the 99th percentile:

   • A change of ≥3 standard deviations around the initial value indicates acute myocardial necrosis 1

3. Absolute changes in high-sensitivity troponin T levels have higher diagnostic accuracy than relative changes 1

Rapid Diagnostic Algorithms

0h/1h Algorithm (Preferred)

• Allows for faster diagnosis than traditional 3-hour protocols
• Requires baseline and 1-hour troponin measurements
• Rule-out criteria: Very low initial value OR low initial value with minimal change at 1h
• Rule-in criteria: High initial value OR significant rise at 1h
• Has >99% negative predictive value and ~75% positive predictive value 1

0h/2h Algorithm (Alternative)

• Similar to 0h/1h but with 2-hour interval
• Second-best option according to ESC guidelines 1

Important Clinical Considerations

1. False Positives: Numerous non-MI conditions can cause troponin elevation:

   • Tachyarrhythmias, heart failure, hypertensive emergencies
   • Myocarditis, Takotsubo syndrome, pulmonary embolism
   • Renal dysfunction, sepsis, neurological events 1, 2

2. Renal Dysfunction: Patients with renal insufficiency require higher cutoff values:

   • eGFR <30 mL/min: ~143 ng/L
   • eGFR 30-59 mL/min: ~54 ng/L
   • eGFR 60-89 mL/min: ~30 ng/L
   • eGFR ≥90 mL/min: ~20 ng/L 3

3. Timing: Troponins may be elevated as early as 2-4 hours after symptom onset, but may not become abnormal for up to 12 hours 1

4. Clinical Context: Interpretation must always include clinical assessment and ECG findings, as solitary elevations cannot be assumed to be due to MI 1, 2

Common Pitfalls to Avoid

1. Using a single troponin value without considering the pattern of change
2. Failing to use assay-specific cutoffs (they vary significantly between manufacturers)
3. Ignoring clinical context when interpreting elevated troponin values
4. Not adjusting thresholds for patients with renal dysfunction
5. Relying on troponin alone without ECG findings and clinical presentation

Remember that the diagnosis of MI requires the appropriate clinical context of myocardial ischemia in addition to the troponin elevation and pattern. Elevated troponin alone is not sufficient for diagnosis of MI/NSTEMI.