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FIB-4 Fibrosis Index Calculator
x402
FIB-4 Fibrosis Index 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 FIB-4 liver fibrosis index from age, AST, ALT, and platelet count for MASH/NASH prior-authorization workflows
Price / call$0.005
Success—
StatusUnknown
How this service works
FIB-4 fibrosis index from age, AST, ALT, and platelets. Use for MASH/NASH prior-auth arithmetic. Deterministic published index with citation; not a diagnosis.
Output
Returns the computed FIB-4 index value (a continuous numeric score) derived from the published Sterling et al. formula: (age × AST) / (platelets × √ALT). The response includes the numeric score, interpretive thresholds (e.g., <1.30 = low risk, >2.67 = high risk), and a citation to the originating publication. No diagnosis is made; the result is deterministic arithmetic based on the four input lab values.
Example use cases
MASH prior-auth documentation
“I need the FIB-4 score for a prior authorization request — the patient is 61 years old, AST is 88 U/L, ALT is 64 U/L, and platelets are 130 × 10⁹/L.”
Liver fibrosis risk stratification
“Can you compute the FIB-4 index for my 47-year-old patient whose labs show AST 45 U/L, ALT 52 U/L, and platelet count 210 × 10⁹/L? I want to see if they're low or high risk for significant fibrosis.”
Serial monitoring of fibrosis index
“Run the FIB-4 calculation for a 58-year-old with today's labs: AST 110 U/L, ALT 78 U/L, platelets 98 × 10⁹/L — I'm tracking whether fibrosis is progressing compared to last quarter.”
Technical details
Endpoint
GEThttps://api.magentlab.com/api/calc/fib4When to prefer
Use this endpoint when you need a deterministic, citable FIB-4 score for MASH/NASH prior-authorization paperwork or clinical decision support and want a zero-configuration arithmetic API rather than a full EHR integration or ML-based fibrosis model. Ideal when you already have the four required lab values (age, AST, ALT, platelets) and need a reproducible, auditable result with a published reference. Prefer this over manual spreadsheet calculation when building automated prior-auth workflows or population health pipelines that require consistent fibrosis staging.
Side effects
- Missing required query parameters (age, ast_u_l, alt_u_l, platelets_10e9_l) returns a 400 validation error
- Out-of-range values (e.g., age < 18 or > 120, platelets < 1 or > 2000, AST/ALT < 1 or > 10000) return validation errors
- Division-by-zero edge case if platelets or ALT is zero (guarded by minimum value constraints)
- Payment failure via x402 protocol returns 402 Payment Required before computation
- Network timeout if the API is unreachable
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"path": "/api/calc/fib4",
"count": 2,
"items": [
{
"fib4": 3.95,
"alt_u_l": 40,
"ast_u_l": 100,
"formula": "fib4",
"citation": {
"id": "sterling-2006",
"doi": "10.1002/hep.21172",
"title": "Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection",
"source": "Hepatology. 2006;43(6):1317-1325",
"authors": "Sterling RK, Lissen E, Clumeck N, et al."
},
"age_years": 50,
"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.",
"sterling_band": "high",
"platelets_10e9_l": 200,
"formula_expression": "FIB-4 = (age_years * AST_U_L) / (platelets_10e9_L * sqrt(ALT_U_L))"
},
{
"fib4": 3.95,
"alt_u_l": 40,
"ast_u_l": 100,
"formula": "fib4",
"citation": {
"id": "sterling-2006",
"doi": "10.1002/hep.21172",
"title": "Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection",
"source": "Hepatology. 2006;43(6):1317-1325",
"authors": "Sterling RK, Lissen E, Clumeck N, et al."
},
"age_years": 50,
"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.",
"sterling_band": "high",
"platelets_10e9_l": 200,
"formula_expression": "FIB-4 = (age_years * AST_U_L) / (platelets_10e9_L * sqrt(ALT_U_L))"
}
]
}
}Tags
x402
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