{"uid":"cap_ZL-yi6JQ2N-R1xlP4rgXo","slug":"cohn-2012-rule-of-7s-for-lyme-meningitis-risk-stratification-7ab6aae3","name":"Cohn 2012 Rule of 7s for Lyme Meningitis Risk Stratification","description":"Cohn 2012 Rule of 7s. Low-risk for Lyme meningitis iff all three hold: headache duration <7 days, CSF mononuclear cells <70%, and no seventh or other cranial-nerve palsy. Seven days and 70% are not low-risk. The caller assigns duration, CSF differential, and palsy. magent does not examine nerves or count CSF cells. Not a Lyme diagnosis, not a medical device, and not a treatment or discharge order. Does not compute Avery 2006 logistic probabilities.","url":"https://api.magentlab.com/api/calc/rule_7s","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":["headache_days","csf_mononuclear_percent","cranial_nerve_palsy"],"properties":{"headache_days":{"type":"integer","description":"Duration of headache in days (integer 0-90). Low-risk criterion holds when strictly less than 7. Seven days is not low-risk. magent does not take a history."},"cranial_nerve_palsy":{"type":"boolean","description":"Seventh or other cranial-nerve palsy. true or false as assigned by the caller. Low-risk criterion holds when false (palsy absent). magent does not examine nerves."},"csf_mononuclear_percent":{"type":"number","description":"CSF mononuclear cell percent (0-100). Low-risk criterion holds when strictly less than 70. Seventy percent is not low-risk. magent does not count CSF cells."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"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_0x-mUyVaIIw74cbE5KbIM","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":"Applies the Cohn 2012 Rule of 7s to classify a patient as low-risk or not-low-risk for Lyme meningitis based on headache duration, CSF mononuclear cell percentage, and cranial-nerve palsy status.","exampleAgentPrompt":"Run the Cohn 2012 Rule of 7s for Lyme meningitis: the patient has had a headache for 4 days, CSF mononuclear cells are 55%, and there is no cranial-nerve palsy — is this patient low-risk?","exampleUseCases":[{"title":"ED Lyme meningitis triage decision","prompt":"A child in the ED has had a headache for 3 days, their CSF shows 60% mononuclear cells, and there's no seventh-nerve palsy — run the Rule of 7s and tell me whether they're low-risk for Lyme meningitis."},{"title":"Borderline CSF result risk check","prompt":"My patient has a 7-day headache, 65% mononuclear cells on CSF, and no cranial-nerve palsy — apply the Cohn Rule of 7s and tell me if they meet low-risk criteria for Lyme meningitis."},{"title":"Cranial nerve palsy present scenario","prompt":"Patient with a 2-day headache and CSF mononuclear percent of 40%, but they have a seventh-nerve palsy — what does the Rule of 7s say about their Lyme meningitis risk?"}],"resultDescription":"Returns whether the patient satisfies all three low-risk criteria of the Cohn 2012 Rule of 7s: headache duration strictly less than 7 days, CSF mononuclear cells strictly less than 70%, and no cranial-nerve palsy. If all three hold, the patient is classified as low-risk for Lyme meningitis; otherwise not low-risk.","failureModes":["Missing required query parameters (headache_days, csf_mononuclear_percent, cranial_nerve_palsy) returns a validation error","headache_days outside integer range 0-90 may return an error","csf_mononuclear_percent outside 0-100 may return an error","Payment not provided or insufficient USDC (x402 protocol) results in a 402 Payment Required response","Caller misinterprets not-low-risk as a Lyme diagnosis — the endpoint does not diagnose"],"whenToPreferThis":"Use this endpoint when you need to quickly apply the Cohn 2012 Rule of 7s threshold logic and the caller has already determined headache duration, CSF differential, and cranial-nerve exam findings. Prefer this over manual calculation to avoid threshold errors (7 and 70 are not low-risk). Do not use if you need Avery 2006 logistic regression probabilities or a full diagnostic workup — this is strictly arithmetic threshold classification.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T00:48:57.160Z","isFirstParty":false}