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MELD-Na calculator x402 API for agents

MELD-Na

Agents must not invent MELD-Na from model memory. This endpoint computes the published OPTN/UNOS 2016 MELD-Na score from creatinine, bilirubin, INR, sodium, and dialysis; pay per request with x402 USDC on Base.

LIVE $0.005 USDC GET /api/calc/meld_na

Markdown: /docs/meld-na.md · Canonical: https://magentlab.com/docs/meld-na

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

What it computes

Agents must not invent MELD-Na from model memory. This endpoint computes the published OPTN/UNOS 2016 MELD-Na score from creatinine, bilirubin, INR, sodium, and dialysis; pay per request with x402 USDC on Base.

When to use

When an agent needs the cited OPTN/UNOS 2016 MELD-Na score rather than a language-model guess, including for liver disease severity arithmetic. Pay per request with x402 USDC. Not a diagnosis or dosing recommendation.

When not to use

  • Not a medical device. Not a listing recommendation or allocation decision.
  • Applies OPTN creatinine/bilirubin/INR floors and sodium clamp (125–137). Dialysis forces creatinine 4.0.
  • Does not compute exception scores or MELD 3.0.

Formula

MELD = round(10 * (0.957*ln(Cr) + 0.378*ln(bili) + 1.120*ln(INR) + 0.643)); if MELD > 11, MELD-Na = round(MELD + 1.32*(137-Na) - 0.033*MELD*(137-Na))

Citation

Title
Serum sodium predicts mortality in patients listed for liver transplantation; OPTN Policy 9 MELD-Na bounds
Authors
Biggins SW, Kim WR, Terrault NA, et al.; OPTN/UNOS
Source
Gastroenterology. 2006;130(6):1652-1660; OPTN Policy 9 (2016)
DOI
10.1053/j.gastro.2006.02.010

Worked example

Cr 1.9, bili 4.2, INR 1.2, Na 128

Given: bilirubin_mg_dl=4.2creatinine_mg_dl=1.9dialysis=falseinr=1.2sodium_mmol_l=128

  1. Clamp labs per OPTN Policy 9 (Na used = 128).
  2. MELD = round(10 * (0.957*ln(Cr) + 0.378*ln(bili) + 1.120*ln(INR) + 0.643))
  3. If MELD > 11, apply the sodium term → MELD-Na

Also searched as

  • MELD-Na
  • OPTN MELD-Na
  • sodium-adjusted MELD
  • UNOS MELD 2016
  • MELD-Na calculator
  • meld na

Try

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

/api/calc/meld_na?creatinine_mg_dl=1.9&bilirubin_mg_dl=4.2&inr=1.2&sodium_mmol_l=128&dialysis=false

Full URL: https://api.magentlab.com/api/calc/meld_na?creatinine_mg_dl=1.9&bilirubin_mg_dl=4.2&inr=1.2&sodium_mmol_l=128&dialysis=false

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/meld_na?creatinine_mg_dl=1.9&bilirubin_mg_dl=4.2&inr=1.2&sodium_mmol_l=128&dialysis=false"

Parameters

Name Type Required Description
creatinine_mg_dl number optional Serum creatinine in mg/dL. Provide this or creatinine_umol_l. OPTN floors at 1 and caps at 4.
creatinine_umol_l number optional Serum creatinine in µmol/L.
bilirubin_mg_dl number optional Total bilirubin in mg/dL (0.1-40). Provide this or bilirubin_umol_l. OPTN floors at 1.
bilirubin_umol_l number optional Total bilirubin in µmol/L. Converted as mg/dL = µmol/L / 17.1.
inr number required INR (0.8-10). OPTN floors at 1.
sodium_mmol_l number required Serum sodium in mmol/L (110-160). OPTN clamps 125-137. Applied only when MELD > 11.
dialysis boolean required Dialysis twice in the last week. true sets creatinine used to 4.0.

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/meld_na 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": [
    {
      "bilirubin_mg_dl": "4.2",
      "creatinine_mg_dl": "1.9",
      "dialysis": "false",
      "inr": "1.2",
      "sodium_mmol_l": "128"
    },
    {
      "bilirubin_mg_dl": "4.2",
      "creatinine_mg_dl": "1.9",
      "dialysis": "false",
      "inr": "1.2",
      "sodium_mmol_l": "128"
    }
  ]
}

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/meld_na",
  "items": [
    {
      "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": "Biggins SW, Kim WR, Terrault NA, et al.; OPTN/UNOS",
        "doi": "10.1053/j.gastro.2006.02.010",
        "id": "optn-meld-na-2016",
        "source": "Gastroenterology. 2006;130(6):1652-1660; OPTN Policy 9 (2016)",
        "title": "Serum sodium predicts mortality in patients listed for liver transplantation; OPTN Policy 9 MELD-Na bounds"
      },
      "formula": "optn_meld_na_2016",
      "formula_expression": "MELD = round(10 * (0.957*ln(Cr) + 0.378*ln(bili) + 1.120*ln(INR) + 0.643)); if MELD > 11, MELD-Na = round(MELD + 1.32*(137-Na) - 0.033*MELD*(137-Na))",
      "sodium_mmol_l": 128.0,
      "creatinine_mg_dl": 1.9,
      "inr": 1.2,
      "bilirubin_mg_dl": 4.2,
      "meld": 20,
      "bilirubin_used_mg_dl": 4.2,
      "creatinine_used_mg_dl": 1.9,
      "dialysis": false,
      "inr_used": 1.2,
      "meld_na": 26,
      "sodium_used_mmol_l": 128.0
    },
    {
      "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": "Biggins SW, Kim WR, Terrault NA, et al.; OPTN/UNOS",
        "doi": "10.1053/j.gastro.2006.02.010",
        "id": "optn-meld-na-2016",
        "source": "Gastroenterology. 2006;130(6):1652-1660; OPTN Policy 9 (2016)",
        "title": "Serum sodium predicts mortality in patients listed for liver transplantation; OPTN Policy 9 MELD-Na bounds"
      },
      "formula": "optn_meld_na_2016",
      "formula_expression": "MELD = round(10 * (0.957*ln(Cr) + 0.378*ln(bili) + 1.120*ln(INR) + 0.643)); if MELD > 11, MELD-Na = round(MELD + 1.32*(137-Na) - 0.033*MELD*(137-Na))",
      "sodium_mmol_l": 128.0,
      "creatinine_mg_dl": 1.9,
      "inr": 1.2,
      "bilirubin_mg_dl": 4.2,
      "meld": 20,
      "bilirubin_used_mg_dl": 4.2,
      "creatinine_used_mg_dl": 1.9,
      "dialysis": false,
      "inr_used": 1.2,
      "meld_na": 26,
      "sodium_used_mmol_l": 128.0
    }
  ]
}

Response

Field Type Description
formula string optn_meld_na_2016
formula_expression string Exact expressions used
creatinine_mg_dl number Input creatinine in mg/dL
bilirubin_mg_dl number Input bilirubin in mg/dL
inr number Input INR
sodium_mmol_l number Input sodium
dialysis boolean Dialysis flag
creatinine_used_mg_dl number Creatinine after OPTN bounds
bilirubin_used_mg_dl number Bilirubin after OPTN floor
inr_used number INR after OPTN floor
sodium_used_mmol_l number Sodium after OPTN clamp
meld integer MELD without sodium, nearest integer
meld_na integer MELD-Na, nearest integer
citation object Biggins 2006 + OPTN Policy 9
disclaimer string Not-a-device notice

Example JSON

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

{
  "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": "Biggins SW, Kim WR, Terrault NA, et al.; OPTN/UNOS",
    "doi": "10.1053/j.gastro.2006.02.010",
    "id": "optn-meld-na-2016",
    "source": "Gastroenterology. 2006;130(6):1652-1660; OPTN Policy 9 (2016)",
    "title": "Serum sodium predicts mortality in patients listed for liver transplantation; OPTN Policy 9 MELD-Na bounds"
  },
  "formula": "optn_meld_na_2016",
  "formula_expression": "MELD = round(10 * (0.957*ln(Cr) + 0.378*ln(bili) + 1.120*ln(INR) + 0.643)); if MELD > 11, MELD-Na = round(MELD + 1.32*(137-Na) - 0.033*MELD*(137-Na))",
  "sodium_mmol_l": 128.0,
  "creatinine_mg_dl": 1.9,
  "inr": 1.2,
  "bilirubin_mg_dl": 4.2,
  "meld": 20,
  "bilirubin_used_mg_dl": 4.2,
  "creatinine_used_mg_dl": 1.9,
  "dialysis": false,
  "inr_used": 1.2,
  "meld_na": 26,
  "sodium_used_mmol_l": 128.0
}

Client errors (HTTP 400)

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

HTTP Code When
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_bilirubin bilirubin_mg_dl (0.1-40) or bilirubin_umol_l (2-684) is required Returned before settlement; you are not charged.
400 invalid_inr inr must be a number from 0.8 to 10 Returned before settlement; you are not charged.
400 invalid_sodium sodium_mmol_l must be a number from 110 to 160 Returned before settlement; you are not charged.
400 invalid_flag boolean clinical flags must be true or false 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

  • FIB-4 — Agents must not invent FIB-4 from model memory. This endpoint computes the published Sterling 2006 FIB-4 fibrosis index from age, AST, ALT, and platelets; pay per request with x402 USDC on Base.
  • Maddrey DF — Compute the 1978 Maddrey discriminant function from patient PT, control PT, and bilirubin.

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.