For healthcare professionals

San Francisco Syncope Rule

The San Francisco Syncope Rule helps sort patients seen for fainting (syncope) by their risk of a serious outcome in the following days. It uses 5 criteria, remembered as CHESS; any one of them means high risk. Quinn and colleagues published it in 2004. This tool is written for clinicians and is not a diagnosis.

Last reviewed: 2026-11-02 By the uncovermyrisk.com editorial team Educational only, not medical advice.

Fainting with chest pain, trouble breathing, a racing or pounding heart, or fainting during exercise: call 911 now.General safety advice (not part of the published rule). The rule is for patients already being assessed; it does not replace urgent care.

Patient findings

Tick each finding that applies. Nothing you enter leaves this page.

CHESS criteria

C: History of congestive heart failureH: Hematocrit below 30%E: Abnormal ECG (non-sinus rhythm on the ECG or on monitoring, or new changes on the ECG)S: Shortness of breathS: Systolic blood pressure below 90 mmHg at triage

Result appears here

What you will see

Whether the rule places the patient at high or low risk, and which criteria were present.

Educational only, not medical advice. Not a diagnosis. Decisions belong to the treating team.

Source

Quinn JV and colleagues, Annals of Emergency Medicine 2004. The criteria are taken from the open-access (CC BY) table by Uit Het Broek and colleagues, Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2023, and match Situ-LaCasse and colleagues, Journal of Clinical Medicine 2026 (CC BY). The wording of the ECG and blood pressure items follows Kayayurt and colleagues, International Journal of Emergency Medicine 2012 (CC BY). The tests check that each of the 5 criteria alone gives high risk and that none gives low risk.

Validated in

Adults seen in the emergency department after syncope. The rule was derived and validated to predict adverse outcomes at 7 and 30 days (Kayayurt 2012). Kayayurt and colleagues tested it in 231 adults aged 18 and over in Turkey.

Limits

The rule is built to be sensitive, so many high-risk patients have no serious outcome. In the validation by Quinn and colleagues it was 98% sensitive and 56% specific (Situ-LaCasse 2026). In the Turkish study it was 87% sensitive and 78% specific for any adverse event (Kayayurt 2012). Low risk does not mean no risk.

The 5 criteria (CHESS)

The patient is at high risk of a serious outcome if 1 or more of the following is present, and at low risk if none is (Uit Het Broek 2023) (Situ-LaCasse 2026):

C: history of congestive heart failure
H: hematocrit below 30%
E: abnormal ECG, meaning a non-sinus rhythm on the ECG or during monitoring, or new changes on the ECG (Kayayurt 2012)
S: shortness of breath
S: systolic blood pressure below 90 mmHg at triage (Kayayurt 2012)

The rule was derived by Quinn and colleagues (Quinn 2004).

Worked example: a patient who fainted, has no heart failure, a hematocrit of 38%, a normal ECG and a blood pressure of 124/78, but reports shortness of breath, meets 1 criterion, so the rule places them at high risk.

What the studies found

In a prospective validation of 791 consecutive emergency department visits for syncope, the rule was 98% sensitive and 56% specific for adverse events, and 6.8% of patients had a serious outcome after the visit (Situ-LaCasse 2026).

In 231 adults in a Turkish emergency department, the rule had a sensitivity of 87% and a specificity of 78% for any adverse event, and a sensitivity of 100% and a specificity of 70% for death (Kayayurt 2012). A scoping review found the rule among the most studied syncope tools in emergency care (Uit Het Broek 2023).

Related calculators

For a points-based score after fainting, see the Canadian Syncope Risk Score. For chest pain, see the HEART score calculator. The shock index calculator divides heart rate by systolic blood pressure, and the NEWS2 score calculator combines 7 vital signs. Other bedside scores are listed under For healthcare professionals.

Sources

Uit Het Broek LG, Ort BBA, Vermeulen H, et al. Risk stratification tools for patients with syncope in emergency medical services and emergency departments: a scoping review. Scand J Trauma Resusc Emerg Med. 2023;31(1):48. doi:10.1186/s13049-023-01102-z. PMID 37723535. Open access (CC BY 4.0). Table: the San Francisco Syncope Rule (CHESS), 1 or more criteria is high risk of a serious outcome; the Canadian Syncope Risk Score points and five bands. pmc.ncbi.nlm.nih.gov/articles/PMC10508018/
Situ-LaCasse E, Wallace N, Wasiak D, et al. A Narrative Review of Syncope Decision Rules: A Case for Point-of-Care Cardiac Ultrasound for Cardiac Syncope. J Clin Med. 2026;15(10):3780. doi:10.3390/jcm15103780. PMID 42194740. Open access (CC BY 4.0). Table 1: San Francisco Syncope Rule, low risk 0 factors, high risk 1 or more, 7-day serious adverse events; text: validation in 791 visits, 98% sensitive, 56% specific. pmc.ncbi.nlm.nih.gov/articles/PMC13207387/
Kayayurt K, Akoglu H, Limon O, et al. Comparison of existing syncope rules and newly proposed anatolian syncope rule to predict short-term serious outcomes after syncope in the Turkish population. Int J Emerg Med. 2012;5:17. doi:10.1186/1865-1380-5-17. PMID 22520447. Open access (CC BY 2.0). 231 adults; SFSR sensitivity 87%, specificity 78% for any adverse event; 100% and 70% for mortality. pmc.ncbi.nlm.nih.gov/articles/PMC3352305/
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. doi:10.1016/s0196-0644(03)00823-0. PMID 14747812. Original paper (cited; the criteria used here are taken from Uit Het Broek 2023, CC BY). doi.org/10.1016/s0196-0644(03)00823-0

Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-11-02. Spotted an error? See About.