emergency & critical caredecision rule

YEARS Algorithm (PE Workup)

The YEARS algorithm simplifies PE diagnosis by combining three clinical items with a variable D-dimer threshold. If no YEARS items are positive, a higher D-dimer threshold (1000 µg/L) is used for exclusion; if ≥1 item is positive, the standard threshold (500 µg/L) applies. This reduces CTPA imaging by ~14% compared to conventional pathways.

inputs

Threshold varies: <1000 if 0 YEARS items, <500 if ≥1 YEARS item

✓ when to use

Use as an alternative to Wells PE + fixed D-dimer for PE workup in adult ED patients with suspected PE. The YEARS algorithm is designed to reduce unnecessary CTPA scans, particularly in younger patients with no YEARS items who have mildly elevated D-dimers (500–1000). Validated in non-pregnant and pregnant populations.

✗ when not to use

Same exclusions as other PE diagnostic pathways: haemodynamically unstable patients need immediate imaging/treatment. The 'PE most likely diagnosis' item is subjective (same limitation as Wells PE). D-dimer assay units must be confirmed before applying thresholds. Not validated in patients already on therapeutic anticoagulation.

clinical pearls

  • The key innovation of YEARS is the variable D-dimer threshold. With 0 YEARS items, using 1000 instead of 500 safely excludes an additional ~12% of patients without CTPA. This particularly benefits younger, lower-risk patients whose D-dimer is mildly elevated.
  • YEARS uses only 3 clinical items (DVT signs, haemoptysis, PE most likely) — simpler than the 7-item Wells PE. However, it still includes the subjective 'PE most likely' criterion.
  • YEARS has been specifically adapted and validated for pregnancy (van der Pol et al., Lancet 2019). The pregnancy-adapted algorithm excludes D-dimer in women with ≥1 YEARS item and proceeds directly to compression ultrasound, then CTPA if CUS negative.
  • D-dimer unit errors are the biggest pitfall. The YEARS thresholds (500 and 1000) are in µg/L FEU. DDU values are approximately half of FEU values. Always confirm your lab's assay calibration.
  • In practice, YEARS and Wells PE + age-adjusted D-dimer are the two most evidence-based PE diagnostic strategies. Both safely reduce CTPA imaging. Choice depends on institutional preference and familiarity.

related tools

wells-peAlternative PE pretest probabilitypercRule-out if low pretest probabilityage-adjusted-ddimerAlternative D-dimer threshold strategyspesiPrognosis once PE confirmed