# Cohn 2012 Rule of 7s for Lyme Meningitis Risk Stratification

> Cohn 2012 Rule of 7s for Lyme Meningitis Risk Stratification is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

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.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/rule_7s
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cohn-2012-rule-of-7s-for-lyme-meningitis-risk-stratification-7ab6aae3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZL-yi6JQ2N-R1xlP4rgXo

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability cohn-2012-rule-of-7s-for-lyme-meningitis-risk-stratification-7ab6aae3
```

Example prompt: 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?

## When to prefer this

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.

## Known failure modes

- 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

## How this service works

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.

## Output

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.

## Request schema (JSON Schema)

```json
{
 "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"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cohn-2012-rule-of-7s-for-lyme-meningitis-risk-stratification-7ab6aae3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)