# CKD-EPI 2021 Race-Free eGFR Calculator

> CKD-EPI 2021 Race-Free eGFR Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-12).

Computes estimated glomerular filtration rate (eGFR) using the race-free CKD-EPI 2021 creatinine equation from age, sex, and serum creatinine

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/egfr_ckd_epi?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ckd-epi-2021-race-free-egfr-calculator-aeb442e8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_icx5YOqdp5jlUhn_PW4XR

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 ckd-epi-2021-race-free-egfr-calculator-aeb442e8
```

Example prompt: Calculate the eGFR for a 58-year-old male with a serum creatinine of 1.8 mg/dL using the race-free CKD-EPI 2021 formula.

## When to prefer this

Use this endpoint whenever an AI agent must not rely on a language model's internal approximation of kidney function — this endpoint applies the exact, deterministic published CKD-EPI 2021 race-free creatinine formula with a citation, making it appropriate for clinical decision support, prior authorization workflows, drug dosing checks, and any context requiring auditable, reproducible eGFR estimates without racial adjustment.

## Known failure modes

- Missing required parameters (age or sex) returns a validation error
- Age outside 18–120 range may return an out-of-range error as CKD-EPI 2021 is validated only in adults
- Neither creatinine_mg_dl nor creatinine_umol_l provided returns an error requiring at least one
- Negative or physiologically implausible creatinine values may be rejected
- Payment not included or insufficient USDC results in HTTP 402 Payment Required

## How this service works

Deterministic published-formula arithmetic plus ICD-10-CM, RxNorm, and LOINC. Pay in USDC on Base via x402.

## Output

Returns a deterministic eGFR value in mL/min/1.73m² computed from the published CKD-EPI 2021 race-free creatinine equation, along with the corresponding CKD stage or kidney function category and a citation to the source formula.

## 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",
      "sex"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (18-120). CKD-EPI 2021 is validated in adults."
      },
      "sex": {
       "enum": [
        "female",
        "male"
       ],
       "type": "string",
       "description": "Sex used by the published equation. female or male."
      },
      "creatinine_mg_dl": {
       "type": "number",
       "description": "Serum creatinine in mg/dL. Provide this or creatinine_umol_l."
      },
      "creatinine_umol_l": {
       "type": "number",
       "description": "Serum creatinine in µmol/L. Converted as mg/dL = µmol/L / 88.42."
      }
     }
    }
   },
   "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/egfr_ckd_epi",
  "count": 2,
  "items": [
   {
    "sex": "female",
    "units": "mL/min/1.73m2",
    "formula": "ckd_epi_2021_creatinine",
    "citation": {
     "id": "inker-2021",
     "doi": "10.1056/NEJMoa2102953",
     "title": "New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race",
     "source": "N Engl J Med. 2021;385(19):1737-1749",
     "authors": "Inker LA, Eneanya ND, Coresh J, et al."
    },
    "age_years": 65,
    "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.",
    "creatinine_mg_dl": 1.1,
    "egfr_ml_min_1_73m2": 55.8,
    "formula_expression": "142 * min(Scr/κ,1)^α * max(Scr/κ,1)^(-1.200) * 0.9938^age * (1.012 if female)"
   },
   {
    "sex": "female",
    "units": "mL/min/1.73m2",
    "formula": "ckd_epi_2021_creatinine",
    "citation": {
     "id": "inker-2021",
     "doi": "10.1056/NEJMoa2102953",
     "title": "New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race",
     "source": "N Engl J Med. 2021;385(19):1737-1749",
     "authors": "Inker LA, Eneanya ND, Coresh J, et al."
    },
    "age_years": 65,
    "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.",
    "creatinine_mg_dl": 1.1,
    "egfr_ml_min_1_73m2": 55.8,
    "formula_expression": "142 * min(Scr/κ,1)^α * max(Scr/κ,1)^(-1.200) * 0.9938^age * (1.012 if female)"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ckd-epi-2021-race-free-egfr-calculator-aeb442e8/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)