# MELD-Na

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/meld_na`
HTML: https://magentlab.com/docs/meld-na
Markdown: https://magentlab.com/docs/meld-na.md

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

## What it computes

Compute OPTN/UNOS 2016 MELD and MELD-Na from creatinine, bilirubin, INR, sodium, and dialysis.

## When to use

When an agent needs the published MELD-Na arithmetic and must not invent the integer score.

## When not to use

- 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

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

## Worked example

### Cr 1.9, bili 4.2, INR 1.2, Na 128

Given: `bilirubin_mg_dl=4.2, creatinine_mg_dl=1.9, dialysis=false, inr=1.2, sodium_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


## Parameters

- `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.

## Response fields

- `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

Frozen fixture. Not a live lookup.

```json
{
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology 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))",
  "creatinine_mg_dl": 1.9,
  "bilirubin_mg_dl": 4.2,
  "bilirubin_used_mg_dl": 4.2,
  "creatinine_used_mg_dl": 1.9,
  "dialysis": false,
  "inr": 1.2,
  "inr_used": 1.2,
  "meld": 20,
  "meld_na": 26,
  "sodium_mmol_l": 128.0,
  "sodium_used_mmol_l": 128.0
}
```

## Errors

- HTTP 400 `invalid_creatinine`: creatinine_mg_dl (0.1-20) or creatinine_umol_l (9-1768) is required Returned before settlement; you are not charged.
- HTTP 400 `invalid_bilirubin`: bilirubin_mg_dl (0.1-40) or bilirubin_umol_l (2-684) is required Returned before settlement; you are not charged.
- HTTP 400 `invalid_inr`: inr must be a number from 0.8 to 10 Returned before settlement; you are not charged.
- HTTP 400 `invalid_sodium`: sodium_mmol_l must be a number from 110 to 160 Returned before settlement; you are not charged.
- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged.
- HTTP 402 `payment_required`: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 `payment_in_progress`: The same authorization nonce is already being settled; retry shortly
- HTTP 429 `rate_limited`: Too many requests from this client
- HTTP 503 `settlement_uncertain`: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 `facilitator_unavailable`: Payment facilitator unavailable
- HTTP 503 `facilitator_misconfigured`: Payment facilitator is not configured
- HTTP 503 `facilitator_unauthorized`: Payment facilitator rejected credentials
- HTTP 503 `ledger_unavailable`: Payment ledger unavailable
- HTTP 503 `payment_unavailable`: Payment processing unavailable

## Related tools

- [FIB-4](https://magentlab.com/docs/fib4) — Compute the FIB-4 fibrosis index from age, AST, ALT, and platelets.

## Also searched as

- MELD-Na
- OPTN MELD-Na
- sodium-adjusted MELD
- UNOS MELD 2016

## Payment

Required query parameters must be present and valid. 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.

## Guarantees

- Invalid query parameters return HTTP 400 before settlement. You are not charged.
- Settlement finishes before the tool executes. Uncertain settlement fails closed (HTTP 503).
- Execution is timeout-bounded and concurrency-capped.
- Calculator inputs are not persisted. Request logs store path without query.