{"uid":"cap_zAvAHcng30bivgxwcmNeo","slug":"san-francisco-syncope-rule-chess-score-calculator-6d17621c","name":"San Francisco Syncope Rule (CHESS Score) Calculator","description":"San Francisco Syncope Rule (CHESS) from history of CHF, hematocrit, abnormal ECG, shortness of breath, and systolic BP. Returns a 0-5 criterion count and rule-positive if any CHESS item is present. Deterministic published score with citation; not a disposition protocol.","url":"https://api.magentlab.com/api/calc/sf_syncope","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","required":["chf","hematocrit_percent","abnormal_ecg","shortness_of_breath","systolic_bp_mm_hg"],"properties":{"chf":{"type":"boolean","description":"History of congestive heart failure (C). true or false."},"abnormal_ecg":{"type":"boolean","description":"Abnormal ECG (E). true or false. Caller-assigned; magent does not read tracings."},"systolic_bp_mm_hg":{"type":"number","description":"Systolic BP in mm Hg (50-250). Scores 1 when <90; 90 is negative."},"hematocrit_percent":{"type":"number","description":"Hematocrit in percent (10-70). Scores 1 when <30; 30 is negative."},"shortness_of_breath":{"type":"boolean","description":"Shortness of breath (S). true or false."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"path":"/api/calc/sf_syncope","count":2,"items":[{"score":0,"formula":"sf_syncope","citation":{"id":"quinn-2004","doi":"10.1016/S0196-0644(03)00823-0","title":"Derivation of the San Francisco Syncope Rule to predict patients with short-term serious outcomes","source":"Ann Emerg Med. 2004;43(2):224-232","authors":"Quinn JV, Stiell IG, McDermott DA, Sellers KL, Kohn MA, Wells GA"},"max_score":5,"components":[{"factor":"chf","points":0,"present":false},{"value":40,"factor":"hematocrit_lt_30","points":0,"present":false},{"factor":"abnormal_ecg","points":0,"present":false},{"factor":"shortness_of_breath","points":0,"present":false},{"value":120,"factor":"systolic_bp_lt_90","points":0,"present":false}],"disclaimer":"Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.","rule_positive":false,"systolic_bp_mm_hg":120,"formula_expression":"CHESS = chf + hematocrit_lt_30 + abnormal_ecg + shortness_of_breath + systolic_bp_lt_90; rule-positive if score ≥ 1; max 5","hematocrit_percent":40},{"score":0,"formula":"sf_syncope","citation":{"id":"quinn-2004","doi":"10.1016/S0196-0644(03)00823-0","title":"Derivation of the San Francisco Syncope Rule to predict patients with short-term serious outcomes","source":"Ann Emerg Med. 2004;43(2):224-232","authors":"Quinn JV, Stiell IG, McDermott DA, Sellers KL, Kohn MA, Wells GA"},"max_score":5,"components":[{"factor":"chf","points":0,"present":false},{"value":40,"factor":"hematocrit_lt_30","points":0,"present":false},{"factor":"abnormal_ecg","points":0,"present":false},{"factor":"shortness_of_breath","points":0,"present":false},{"value":120,"factor":"systolic_bp_lt_90","points":0,"present":false}],"disclaimer":"Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.","rule_positive":false,"systolic_bp_mm_hg":120,"formula_expression":"CHESS = chf + hematocrit_lt_30 + abnormal_ecg + shortness_of_breath + systolic_bp_lt_90; rule-positive if score ≥ 1; max 5","hematocrit_percent":40}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_1pjuKgxiMiMMbv6mypryv","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates the San Francisco Syncope Rule (CHESS) score from five clinical criteria to identify high-risk syncope patients, returning a criterion count (0–5) and rule-positive flag.","exampleAgentPrompt":"Score this syncope patient on the San Francisco Syncope Rule: they have a history of CHF, hematocrit is 27%, ECG is abnormal, no shortness of breath, and systolic BP is 105 mm Hg.","exampleUseCases":[{"title":"ED syncope triage risk flagging","prompt":"I have a syncope patient in the ED — history of CHF is yes, hematocrit 24%, ECG shows bundle branch block so mark that abnormal, no shortness of breath, and systolic BP is 88. Run the SF Syncope Rule and tell me if they're rule-positive."},{"title":"Automatic chart-based CHESS scoring","prompt":"Pull the CHESS score for this patient: no CHF history, hematocrit 35%, ECG is normal, they did complain of shortness of breath, and their systolic BP on arrival was 95 mm Hg."},{"title":"Clinical documentation QA for syncope visits","prompt":"Check whether our attending should have flagged this syncope case as high-risk: CHF history negative, hematocrit 31%, ECG normal, no dyspnea, systolic BP 120. What does the SF Syncope Rule say?"}],"resultDescription":"Returns the total number of CHESS criteria met (integer 0–5) and a boolean rule-positive flag indicating whether any single criterion is present, which per the published rule identifies high-risk syncope. Individual criterion contributions are also available to explain which items scored positive.","failureModes":["Missing required query parameters (chf, hematocrit_percent, abnormal_ecg, shortness_of_breath, systolic_bp_mm_hg) returns a validation error","Hematocrit value outside accepted range (10–70%) returns an out-of-range error","Systolic BP value outside accepted range (50–250 mm Hg) returns an out-of-range error","Non-boolean values passed for boolean parameters return a type error","Payment not included or insufficient USDC triggers a 402 Payment Required response"],"whenToPreferThis":"Use this endpoint when you need a deterministic, citation-backed implementation of the San Francisco Syncope Rule (CHESS) for syncope risk stratification — particularly when building clinical decision support workflows, automating chart review, or auditing ED syncope management. Prefer this over general-purpose LLM reasoning for medical scoring because it guarantees adherence to the published Elesber/Quinn algorithm with traceable citation, not probabilistic generation. It is not a disposition protocol and should be used alongside clinical judgment.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T01:09:14.374Z","isFirstParty":false}