# CHADS2 Stroke Risk Score Calculator > CHADS2 Stroke Risk Score Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15). Computes the CHADS2 atrial fibrillation stroke-risk score from five discrete clinical flags using the 2001 Gage methodology ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/chads2 - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-15 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/chads2-stroke-risk-score-calculator-6b8646a9 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XzvhhrpfCA8tWUq3gTAWH 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 chads2-stroke-risk-score-calculator-6b8646a9 ``` Example prompt: Calculate the CHADS2 stroke risk score for a 78-year-old patient with atrial fibrillation who has hypertension and diabetes but no congestive heart failure and no prior stroke or TIA. ## When to prefer this Use this endpoint when you need a deterministic, citation-backed CHADS2 score calculation based on the original 2001 Gage methodology for atrial fibrillation stroke risk stratification. Prefer this over CHA2DS2-VASc calculators when specifically required to use the simpler 2001 5-factor model. Suitable for automated clinical workflows, EHR enrichment, or decision-support pipelines where reproducible arithmetic and a published citation are required. ## Known failure modes - Missing required query parameter returns validation error - Age out of valid range (18–120) returns error - Non-boolean value for clinical flag fields returns parsing error - Network timeout if upstream service is unavailable ## How this service works CHADS2 score from discrete clinical flags. Use for the 2001 Gage atrial-fibrillation stroke-risk arithmetic. Deterministic published score with citation; not an anticoagulation order. ## Output Returns the integer CHADS2 score (0–6) computed from the five input clinical flags per the 2001 Gage methodology, along with interpretive context and the published citation. Higher scores indicate greater annual stroke risk in patients with atrial fibrillation. ## 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": [ "age", "chf", "hypertension", "diabetes", "stroke_tia" ], "properties": { "age": { "type": "integer", "description": "Age in years (18-120). ≥75 scores 1." }, "chf": { "type": "boolean", "description": "Congestive heart failure or LV dysfunction. true or false." }, "diabetes": { "type": "boolean", "description": "Diabetes mellitus. true or false." }, "stroke_tia": { "type": "boolean", "description": "Prior stroke or TIA. true or false (2 points)." }, "hypertension": { "type": "boolean", "description": "Hypertension history. true or false." } } } }, "additionalProperties": false }, "output": { "type": "object", "required": [ "type" ], "properties": { "type": { "type": "string" }, "example": { "type": "object" } } } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "path": "/api/calc/chads2", "count": 2, "items": [ { "score": 3, "formula": "chads2", "citation": { "id": "gage-2001", "doi": "10.1001/jama.285.22.2864", "title": "Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation", "source": "JAMA. 2001;285(22):2864-2870", "authors": "Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ" }, "age_years": 78, "max_score": 6, "components": [ { "factor": "congestive_heart_failure", "points": 0, "present": false }, { "factor": "hypertension", "points": 1, "present": true }, { "value": 78, "factor": "age_ge_75", "points": 1, "present": true }, { "factor": "diabetes", "points": 1, "present": true }, { "factor": "stroke_tia", "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.", "formula_expression": "CHADS2 = CHF 1 + hypertension 1 + age≥75 1 + diabetes 1 + stroke/TIA 2; max 6" }, { "score": 3, "formula": "chads2", "citation": { "id": "gage-2001", "doi": "10.1001/jama.285.22.2864", "title": "Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation", "source": "JAMA. 2001;285(22):2864-2870", "authors": "Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ" }, "age_years": 78, "max_score": 6, "components": [ { "factor": "congestive_heart_failure", "points": 0, "present": false }, { "factor": "hypertension", "points": 1, "present": true }, { "value": 78, "factor": "age_ge_75", "points": 1, "present": true }, { "factor": "diabetes", "points": 1, "present": true }, { "factor": "stroke_tia", "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.", "f … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chads2-stroke-risk-score-calculator-6b8646a9/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)