# MELD Score Calculator

> Computes the Model for End-Stage Liver Disease score from bilirubin, INR and creatinine (with the OPTN bounding and rounding rules) and MELD-Na when sodium is supplied, and reports the observed 3-month mortality band from Wiesner 2003.

- Calculator id: `meld-score` · Category: Medical & Clinical (`medical`) · Tool name: `calculate_meld_score`
- Canonical page: https://tttkmbb.com/medical/meld-score · This document: https://tttkmbb.com/medical/meld-score.md · JSON definition: https://tttkmbb.com/medical/meld-score.json

## Purpose

Computes the Model for End-Stage Liver Disease score from bilirubin, INR and creatinine (with the OPTN bounding and rounding rules) and MELD-Na when sodium is supplied, and reports the observed 3-month mortality band from Wiesner 2003.

**Use when:** You need the MELD or MELD-Na score for an adult with chronic liver disease, for example to compare severity or describe transplant listing priority.

**Do not use when:** The patient is under 12 (PELD is used) or you need the newer MELD 3.0 (adds albumin and sex), which this calculator does not implement.

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `bilirubin_mg_dl` | number | mg/dL | required | Serum total bilirubin in mg/dL (µmol/L ÷ 17.1). Values below 1 are set to 1. (> 0, max 100) |
| `inr` | number |  | required | International normalised ratio. Values below 1 are set to 1. (min 0.5, max 20) |
| `creatinine_mg_dl` | number | mg/dL | required | Serum creatinine in mg/dL (µmol/L ÷ 88.4). Bounded to 1–4. (> 0, max 30) |
| `sodium_mmol_l` | number | mmol/L | optional | Optional serum sodium; enables MELD-Na (bounded to 125–137). (min 100, max 200) |
| `dialysis_twice_past_week` | boolean |  | optional, default false | If true, creatinine is set to 4.0 mg/dL as in the OPTN policy. |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `meld_score` | integer |  | MELD(i) without sodium, rounded and bounded to 6–40. |
| `meld_na_score` | integer |  | 2016 OPTN MELD-Na (only when sodium_mmol_l is given), bounded to 6–40. |
| `three_month_mortality_percent` | number | % | Wiesner 2003 band for MELD-Na when available, otherwise MELD. |
| `mortality_band` | string |  | Score band and observed mortality from Wiesner et al. 2003. |
| `values_used` | string |  | Laboratory values after the OPTN bounds were applied. |

## Formula

`MELD(i) = 0.957 × ln(creatinine) + 0.378 × ln(bilirubin) + 1.120 × ln(INR) + 0.643, rounded to one decimal and multiplied by 10 (values < 1 set to 1; creatinine capped at 4 or set to 4 with dialysis). If MELD(i) > 11: MELD-Na = MELD(i) + 1.32 × (137 − Na) − 0.033 × MELD(i) × (137 − Na), Na bounded 125–137. Final scores rounded and bounded to 6–40.`

Kamath 2001 coefficients (3.78, 11.2, 9.57, 6.43 in the ×10 form); mortality bands are the 3-month waiting-list mortality observed by Wiesner 2003 (≤9: 1.9%, 10–19: 6.0%, 20–29: 19.6%, 30–39: 52.6%, 40: 71.3%). Results are informational only and not a substitute for clinical judgement or medical advice.

## Data Sources

- Kamath PS et al. (2001) A model to predict survival in patients with end-stage liver disease, Hepatology 33:464-470 — https://pubmed.ncbi.nlm.nih.gov/11172350/ (peer_reviewed, retrieved 2026-09-24)
- Wiesner R et al. (2003) Model for end-stage liver disease (MELD) and allocation of donor livers, Gastroenterology 124:91-96 — https://pubmed.ncbi.nlm.nih.gov/12512033/ (peer_reviewed, retrieved 2026-09-24)
- OPTN/HRSA policy notice – Improving liver allocation: MELD, PELD, Status 1A, Status 1B (MELD-Na formula) — https://www.hrsa.gov/sites/default/files/hrsa/optn/policy-guid-change_impr-liv-alloc-meld-peld-sta-1a-sta-1b_liv.pdf (government, retrieved 2026-09-24)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/meld-score?bilirubin_mg_dl=…&inr=…&creatinine_mg_dl=…`
- `POST https://tttkmbb.com/api/v1/calculate/meld-score` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/meld-score · OpenAPI operationId `calculate_meld_score` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "meld-score", "inputs": {…}}`

## Example

- Bilirubin 2.0, INR 1.5, creatinine 1.2, Na 135: inputs `{"bilirubin_mg_dl":2,"inr":1.5,"creatinine_mg_dl":1.2,"sodium_mmol_l":135}` → `{"meld_score":15,"meld_na_score":17,"three_month_mortality_percent":6}`
- Bilirubin 5.0, INR 2.5, creatinine 2.0, Na 128: inputs `{"bilirubin_mg_dl":5,"inr":2.5,"creatinine_mg_dl":2,"sodium_mmol_l":128}` → `{"meld_score":29,"meld_na_score":32,"three_month_mortality_percent":52.6}`
- Bilirubin 0.8, INR 1.0, creatinine 0.9 (all bounded to 1): inputs `{"bilirubin_mg_dl":0.8,"inr":1,"creatinine_mg_dl":0.9}` → `{"meld_score":6,"three_month_mortality_percent":1.9}`

```
GET https://tttkmbb.com/api/v1/calculate/meld-score?bilirubin_mg_dl=2&inr=1.5&creatinine_mg_dl=1.2&sodium_mmol_l=135
```

## Limitations

The patient is under 12 (PELD is used) or you need the newer MELD 3.0 (adds albumin and sex), which this calculator does not implement. Kamath 2001 coefficients (3.78, 11.2, 9.57, 6.43 in the ×10 form); mortality bands are the 3-month waiting-list mortality observed by Wiesner 2003 (≤9: 1.9%, 10–19: 6.0%, 20–29: 19.6%, 30–39: 52.6%, 40: 71.3%). Results are informational only and not a substitute for clinical judgement or medical advice. All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Why is my score different from an older calculator?**

Pre-2016 calculators used the un-rounded Kamath formula or omitted sodium; this one follows the OPTN rounding (MELD(i) to one decimal × 10) and adds the sodium term only when MELD(i) exceeds 11.

**Are the mortality percentages predictions for an individual?**

No. They are the mortality observed in waiting-list cohorts in 2003 for each score band; individual prognosis depends on complications and treatment.

## Related

- [eGFR Calculator](https://tttkmbb.com/medical/egfr.md) — Kidney function is a MELD component.
- [Anion Gap Calculator](https://tttkmbb.com/medical/anion-gap.md) — Electrolyte assessment in decompensated cirrhosis.