# GAP Index Calculator (Ley 2012) > GAP Index Calculator (Ley 2012) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11). Computes the Ley 2012 GAP (Gender, Age, Physiology) index total score (0–8) and stage (1–3) for idiopathic pulmonary fibrosis prognosis ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/gap_index?utm_source=zero.xyz - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-10-11 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/gap-index-calculator-ley-2012-08ea2ae0 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_l0GUkCAGGBUv6h3v4LNUC 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 gap-index-calculator-ley-2012-08ea2ae0 ``` Example prompt: Calculate the GAP index for a 68-year-old male patient with an FVC of 62% predicted and a DLCO of 48% predicted — give me the total score and stage. ## When to prefer this Use this endpoint when you need a deterministic, citation-backed implementation of the Ley 2012 GAP index specifically — not a continuous or custom variant. It is ideal for clinical documentation, prior-authorization support, or EHR integration where a reproducible, auditable score is required. Prefer this over manual calculation whenever sex, age, FVC % predicted, and DLCO % predicted (or a cannot-perform flag) are available. ## Known failure modes - Missing required parameter (sex, age, or fvc_percent_predicted) returns a 400-level error - Supplying both dlco_percent_predicted and dlco_cannot_perform=true simultaneously returns a validation error - Age or FVC values outside allowed ranges (age 18–120, FVC 10–150) may be rejected - DLCO value outside range 1–150 is rejected - Network or service errors return a 5xx response ## How this service works Deterministic published-formula arithmetic plus ICD-10-CM, RxNorm, and LOINC. Pay in USDC on Base via x402. ## Output Returns the individual point contributions for sex, age, FVC, and DLCO, the total GAP score (0–8), and the corresponding GAP stage (Stage 1 for 0–3, Stage 2 for 4–5, Stage 3 for 6–8), with citation to Ley 2012. ## 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": [ "sex", "age", "fvc_percent_predicted" ], "properties": { "age": { "type": "integer", "description": "Age in years (integer 18-120). Ley 2012: <=60 scores 0; 61-65 scores 1; >65 scores 2." }, "sex": { "enum": [ "female", "male" ], "type": "string", "description": "Sex (female or male). Ley 2012: female scores 0; male scores 1." }, "dlco_cannot_perform": { "type": "boolean", "description": "true when DLCO cannot be performed (Ley 2012 scores 3). Provide this or dlco_percent_predicted, not both." }, "fvc_percent_predicted": { "type": "number", "description": "FVC percent predicted (10-150). Ley 2012: >75 scores 0; 50-75 scores 1; <50 scores 2. 75.0 scores 1." }, "dlco_percent_predicted": { "type": "number", "description": "DLCO percent predicted (1-150). Provide this or dlco_cannot_perform=true, not both. Ley 2012: >55 scores 0; 36-55 scores 1; <=35 scores 2." } } } }, "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/gap_index", "count": 2, "items": [ { "sex": "female", "score": 0, "formula": "gap_index", "citation": { "id": "ley-2012", "doi": "10.7326/0003-4819-156-10-201205150-00004", "pmid": "22586007", "title": "A multidimensional index and staging system for idiopathic pulmonary fibrosis", "source": "Ann Intern Med. 2012;156(10):684-691", "authors": "Ley B, Ryerson CJ, Vittinghoff E, et al." }, "age_years": 55, "gap_stage": 1, "max_score": 8, "components": [ { "value": "female", "factor": "sex", "points": 0, "present": false }, { "value": 55, "factor": "age", "points": 0, "present": false }, { "value": 80, "factor": "fvc", "points": 0, "present": false }, { "value": 60, "factor": "dlco", "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": "GAP = sex_points + age_points + fvc_points + dlco_points; female 0 male 1; age <=60 -> 0, 61-65 -> 1, >65 -> 2; FVC% >75 -> 0, 50-75 -> 1, <50 -> 2; DLCO% >55 -> 0, 36-55 -> 1, <=35 -> 2, cannot perform -> 3; stages I 0-3 / II 4-5 / III 6-8; max 8", "dlco_cannot_perform": false, "fvc_percent_predicted": 80, "dlco_percent_predicted": 60 }, { "sex": "female", "score": 0, "formula": "gap_index", "citation": { "id": "ley-2012", "doi": "10.7326/0003-4819-156-10-201205150-00004", "pmid": "22586007", "title": "A multidimensional index and staging system for idiopathic pulmonary fibrosis", "source": "Ann Intern Med. 2012;156(10):684-691", "authors": "Ley B, Ryerson CJ, Vittinghoff E, et al." }, "age_years": 55, "gap_stage": 1, "max_score": 8, "components": [ { "value": "female", "factor": "sex", "points": 0, "present": false }, { "value": 55, "factor": "age", "points": 0, "present": false }, { "value": 80, "factor": "fvc", "points": 0, "present": false }, { "value": 60, "factor": "dlco", "points": 0, "present": false } ], "disclaimer": "Not … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gap-index-calculator-ley-2012-08ea2ae0/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)