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Emergency Medicine · Neurology

Ottawa Subarachnoid Hemorrhage Rule calculator

Enter the published formula inputs below to calculate and interpret this score.

Clinical inputs

Result

0

Ottawa SAH rule low-risk count (0 criteria)

Interpret only within the cited source population and criteria; use alongside complete clinical assessment.

Formula inputs

  • age ge 40
  • neck pain or stiffness
  • arrival by ambulance
  • witnessed loss of consciousness
  • onset during exertion
  • thunderclap headache
  • limited neck flexion

Primary source

Perry JJ et al. Clinical decision rules to predict subarachnoid hemorrhage in patients with acute headache. CMAJ. DOI: 10.1503/cmaj.091816. PMID: 20530183. Scope: count of high-risk Ottawa SAH predictors (age ≥40, neck pain/stiffness, ambulance arrival, witnessed LOC, exertional onset, thunderclap headache, limited neck flexion); 0 criteria indicates low-risk classification in the derivation/validation cohorts. (2010)

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