CrCl calculator x402 API for agents

Cockcroft–Gault CrCl

Agents must not invent CrCl from model memory. This endpoint computes published Cockcroft–Gault creatinine clearance in mL/min using total body weight; pay per request with x402 USDC on Base.

LIVE $0.005 USDC GET /api/calc/crcl_cockcroft_gault

Markdown: /docs/crcl.md · Canonical: https://magentlab.com/docs/crcl

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Agents must not invent CrCl from model memory. This endpoint computes published Cockcroft–Gault creatinine clearance in mL/min using total body weight; pay per request with x402 USDC on Base.

When to use

When an agent needs the cited Cockcroft–Gault creatinine-clearance equation rather than a language-model guess, including when a label still doses on CrCl rather than CKD-EPI eGFR. Pay per request with x402 USDC. Not a diagnosis or dosing recommendation.

When not to use

Not a medical device. Not a treatment recommendation and not a dosing recommendation.
Weight basis is always total body weight. Ideal or adjusted body weight is not applied; call IBW separately if a protocol needs AdjBW.
Does not convert BUN to creatinine.

Formula

CrCl_mL_min = ((140 - age) * weight_kg * (0.85 if female else 1)) / (72 * Scr_mg_dL)

Citation

Title: Prediction of creatinine clearance from serum creatinine
Authors: Cockcroft DW, Gault MH
Source: Nephron. 1976;16(1):31-41
DOI: 10.1159/000180580

Worked example

Age 65 female, 70 kg, Scr 1.1

Given: age=65creatinine_mg_dl=1.1sex=femaleweight_kg=70

CrCl = ((140 - 65) * 70 * 0.85) / (72 * 1.1)
Round to 1 decimal

Also searched as

Cockcroft-Gault
creatinine clearance
CrCl TBW
renal dosing CrCl
CrCl calculator

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/crcl_cockcroft_gault?age=65&sex=female&weight_kg=70&creatinine_mg_dl=1.1

Full URL: https://api.magentlab.com/api/calc/crcl_cockcroft_gault?age=65&sex=female&weight_kg=70&creatinine_mg_dl=1.1

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/crcl_cockcroft_gault?age=65&sex=female&weight_kg=70&creatinine_mg_dl=1.1"

Parameters

Name	Type	Required	Description
`age`	integer	required	Age in years (18-120).
`sex`	string	required · female, male	female applies the published 0.85 factor; male does not.
`weight_kg`	number	optional	Total body weight in kilograms. Provide weight_kg or weight_lb.
`weight_lb`	number	optional	Total body weight in pounds. Converted as kg = lb * 0.45359237.
`creatinine_mg_dl`	number	optional	Serum creatinine in mg/dL. Provide this or creatinine_umol_l.
`creatinine_umol_l`	number	optional	Serum creatinine in µmol/L. Converted as mg/dL = µmol/L / 88.42.

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/crcl_cockcroft_gault Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

1 to 25 items. Each item uses the same keys as the GET query parameters.
POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "age": "65",
      "creatinine_mg_dl": "1.1",
      "sex": "female",
      "weight_kg": "70"
    },
    {
      "age": "65",
      "creatinine_mg_dl": "1.1",
      "sex": "female",
      "weight_kg": "70"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/crcl_cockcroft_gault",
  "items": [
    {
      "units": "mL/min",
      "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.",
      "citation": {
        "authors": "Cockcroft DW, Gault MH",
        "doi": "10.1159/000180580",
        "id": "cockcroft-1976",
        "source": "Nephron. 1976;16(1):31-41",
        "title": "Prediction of creatinine clearance from serum creatinine"
      },
      "formula": "cockcroft_gault",
      "formula_expression": "CrCl_mL_min = ((140 - age) * weight_kg * (0.85 if female else 1)) / (72 * Scr_mg_dL)",
      "age_years": 65,
      "creatinine_mg_dl": 1.1,
      "weight_kg": 70.0,
      "sex": "female",
      "crcl_ml_min": 56.3,
      "weight_basis": "total_body_weight"
    },
    {
      "units": "mL/min",
      "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.",
      "citation": {
        "authors": "Cockcroft DW, Gault MH",
        "doi": "10.1159/000180580",
        "id": "cockcroft-1976",
        "source": "Nephron. 1976;16(1):31-41",
        "title": "Prediction of creatinine clearance from serum creatinine"
      },
      "formula": "cockcroft_gault",
      "formula_expression": "CrCl_mL_min = ((140 - age) * weight_kg * (0.85 if female else 1)) / (72 * Scr_mg_dL)",
      "age_years": 65,
      "creatinine_mg_dl": 1.1,
      "weight_kg": 70.0,
      "sex": "female",
      "crcl_ml_min": 56.3,
      "weight_basis": "total_body_weight"
    }
  ]
}

Response

Field	Type	Description
`formula`	string	cockcroft_gault
`formula_expression`	string	Exact expression used
`age_years`	integer	Age used in the equation
`sex`	string	female or male
`weight_kg`	number	Total body weight in kg
`creatinine_mg_dl`	number	Normalized creatinine
`crcl_ml_min`	number	Creatinine clearance in mL/min, 1 decimal place
`units`	string	mL/min
`weight_basis`	string	Always total_body_weight. Ideal/adjusted body weight is not applied.
`citation`	object	Nephron 1976 citation
`disclaimer`	string	Not-a-device notice

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "units": "mL/min",
  "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.",
  "citation": {
    "authors": "Cockcroft DW, Gault MH",
    "doi": "10.1159/000180580",
    "id": "cockcroft-1976",
    "source": "Nephron. 1976;16(1):31-41",
    "title": "Prediction of creatinine clearance from serum creatinine"
  },
  "formula": "cockcroft_gault",
  "formula_expression": "CrCl_mL_min = ((140 - age) * weight_kg * (0.85 if female else 1)) / (72 * Scr_mg_dL)",
  "age_years": 65,
  "creatinine_mg_dl": 1.1,
  "weight_kg": 70.0,
  "sex": "female",
  "crcl_ml_min": 56.3,
  "weight_basis": "total_body_weight"
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

HTTP	Code	When
400	`invalid_age`	age must be an integer from 18 to 120 Returned before settlement; you are not charged.
400	`invalid_sex`	sex must be female or male Returned before settlement; you are not charged.
400	`invalid_weight`	weight_kg (1-500) or weight_lb (2-1100) is required Returned before settlement; you are not charged.
400	`invalid_creatinine`	creatinine_mg_dl (0.1-20) or creatinine_umol_l (9-1768) is required Returned before settlement; you are not charged.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

CKD-EPI 2021 eGFR — Agents must not invent eGFR from model memory. This endpoint computes published race-free CKD-EPI 2021 creatinine eGFR in mL/min/1.73m2; pay per request with x402 USDC on Base.
Devine IBW — Compute Devine ideal body weight and 0.4 adjusted body weight from height, sex, and actual weight.
FENa — Compute fractional excretion of sodium from plasma and urine sodium and creatinine using Espinel 1976.
FEUrea — Compute fractional excretion of urea (FEUN) from BUN, urine urea nitrogen, plasma creatinine, and urine creatinine.

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /docs/mcp.

Guarantees

HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
Execution is timeout-bounded and concurrency-capped.
Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.