San Francisco Syncope Rule Calculator

San Francisco Syncope Rule (CHESS) for 7-day serious-outcome risk after syncope.

For educational and clinical reference. Not a substitute for medical judgment. See the medical disclaimer.
Score
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Interpretation
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References

  1. Quinn JV, Stiell IG, McDermott DA, et al. Derivation of the San Francisco Syncope Rule to predict patients with short-term serious outcomes. Ann Emerg Med. 2004;43(2):224-232.

How to use

  1. Select each of the five CHESS factors that is present.
  2. Any single positive factor classifies the patient as high risk.
  3. Use as an adjunct to clinical judgment for syncope disposition.

Frequently asked questions

What is the San Francisco Syncope Rule?

A decision rule (mnemonic CHESS) that identifies emergency-department syncope patients at risk of a serious outcome within 7 days. Any one positive factor classifies the patient as high risk.

What counts as a serious outcome?

Death, myocardial infarction, arrhythmia, pulmonary embolism, stroke, subarachnoid hemorrhage, significant hemorrhage, or any condition causing return ED visit and hospitalization.

How sensitive is the rule?

Original derivation reported ≈ 96% sensitivity for serious outcomes, but external validation has shown lower sensitivity — use clinical judgment alongside it.

Does a negative rule allow discharge?

A CHESS-negative result supports lower risk but does not replace assessment for cardiac syncope or a structured disposition decision.

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