Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    San Francisco Syncope Rule

    Defines high-risk criteria for patients with syncope.
    When to Use
    Why Use

    Patients with unexplained syncope can be risk stratified with these criteria.

    Syncope is common and is a common reason for seeking medical attention. The vast majority of syncope is benign, however occasionally syncope can be a sign of a life-threatening disease.


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    Next Steps
    Creator Insights


    Follow institutional guidelines for evaluation of syncope; consider admission and telemetry monitoring, especially for patients with any of the SF Syncope Criteria.


    Series of Yes/No Questions; if any answered “Yes” patient cannot be considered “Low Risk.”

    Facts & Figures

    This rule has a 96% sensitivity and 62% specificity for serious outcome - negative predictive value: 99.2%; positive predictive value 24.8%. However, an external validation at the Albert Einstein College of Medicine showed a lower sensitivity of 74%.

    Serious outcome in this study is defined as "death, myocardial infarction, arrhythmia, pulmonary embolism, stroke, subarachnoid hemorrhage, significant hemorrhage, or any condition causing a return ED visit and hospitalization for a related event."

    Dr. Ian Stiell

    About the Creator

    Ian Stiell, MD, MSc, FRCPC, is Professor and Chair, Department of Emergency Medicine, University of Ottawa; Distinguished Professor and University Health Research Chair, University of Ottawa; Senior Scientist, Ottawa Hospital Research Institute; and Emergency Physician, The Ottawa Hospital. He is internationally recognized for his research in emergency medicine with a focus on the development of clinical decision rules and the conduct of clinical trials involving acutely ill and injured patients treated by prehospital services and in emergency departments. He is best known for the development of the Ottawa Ankle Rule, the Canadian C-Spine Rule, and Canadian CT Head Rule and as the Principal Investigator for the landmark OPALS Studies for prehospital care. Dr. Stiell is the Principal Investigator for 1 of 3 Canadian sites in the Resuscitation Outcomes Consortium (ROC) which is funded by CIHR, NIH, HSFC, AHA, and National Defence Canada. Dr. Stiell is a Member of the Institute of Medicine of the U.S. National Academies of Science.

    To read more about Dr. Stiell's work, visit his website.

    To view Dr. Ian Stiell's publications, visit PubMed

    About the Creator
    Dr. Ian Stiell