# Maddrey DF

Status: WEDGE
Price: $0.005 USDC
`GET /api/calc/maddrey`
HTML: https://magentlab.com/docs/maddrey
Markdown: https://magentlab.com/docs/maddrey.md

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

## What it computes

Compute the 1978 Maddrey discriminant function from patient PT, control PT, and bilirubin.

## When to use

When an agent needs the published 1978 PT-seconds arithmetic and must not substitute INR.

## When not to use

- Not a diagnosis or treatment order. magent does not recommend corticosteroids or any other therapy.
- Uses prothrombin time in seconds versus laboratory control, as published in 1978. Does not accept or convert INR.
- Later trials used DF ≥ 32 as a severity cut. That threshold is later-trial context, not a 1978 treatment band, and is not returned here.

## Formula

```
DF = 4.6 * (pt_patient_sec - pt_control_sec) + bilirubin_mg_dl
```

## Citation

Corticosteroid therapy of alcoholic hepatitis
Maddrey WC, Boitnott JK, Bedine MS, Weber FL Jr, Mezey E, White RI Jr
Gastroenterology. 1978;75(2):193-199
DOI: [10.1016/0016-5085(78)90401-8](https://doi.org/10.1016/0016-5085(78)90401-8)

## Worked example

### PT 20s, control 12s, bilirubin 8 mg/dL

Given: `bilirubin_mg_dl=8, pt_control_sec=12, pt_patient_sec=20`

1. PT difference = 20 − 12 = 8 s
2. DF = 4.6 × 8 + 8 = 44.8


## Parameters

- `pt_patient_sec` (number, required): Patient prothrombin time in seconds (8-120). INR is not accepted.
- `pt_control_sec` (number, required): Laboratory control prothrombin time in seconds (8-20). INR is not accepted.
- `bilirubin_mg_dl` (number, optional): Total bilirubin in mg/dL (0.1-40). Provide this or bilirubin_umol_l.
- `bilirubin_umol_l` (number, optional): Total bilirubin in µmol/L (2-684). Converted as mg/dL = µmol/L / 17.1.

## Bulk (POST)

POST the same path with a JSON items array. Price is n times the GET unit. Invalid items return HTTP 400 before settlement.

Method: `POST /api/calc/maddrey`
Max items: 25
Price: unit_amount * n (unit 5000 atomic)
Status: PREVIEW

- 1 to 25 items. Each item uses the same keys as the GET query parameters.
- 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:

```json
{
  "items": [
    {
      "bilirubin_mg_dl": "8",
      "pt_control_sec": "12",
      "pt_patient_sec": "20"
    },
    {
      "bilirubin_mg_dl": "8",
      "pt_control_sec": "12",
      "pt_patient_sec": "20"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/maddrey

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/maddrey",
  "items": [
    {
      "df": 44.8,
      "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": "Maddrey WC, Boitnott JK, Bedine MS, Weber FL Jr, Mezey E, White RI Jr",
        "doi": "10.1016/0016-5085(78)90401-8",
        "id": "maddrey-1978",
        "source": "Gastroenterology. 1978;75(2):193-199",
        "title": "Corticosteroid therapy of alcoholic hepatitis"
      },
      "formula": "maddrey_1978",
      "formula_expression": "DF = 4.6 * (pt_patient_sec - pt_control_sec) + bilirubin_mg_dl",
      "bilirubin_mg_dl": 8.0,
      "pt_control_sec": 12.0,
      "pt_patient_sec": 20.0
    },
    {
      "df": 44.8,
      "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": "Maddrey WC, Boitnott JK, Bedine MS, Weber FL Jr, Mezey E, White RI Jr",
        "doi": "10.1016/0016-5085(78)90401-8",
        "id": "maddrey-1978",
        "source": "Gastroenterology. 1978;75(2):193-199",
        "title": "Corticosteroid therapy of alcoholic hepatitis"
      },
      "formula": "maddrey_1978",
      "formula_expression": "DF = 4.6 * (pt_patient_sec - pt_control_sec) + bilirubin_mg_dl",
      "bilirubin_mg_dl": 8.0,
      "pt_control_sec": 12.0,
      "pt_patient_sec": 20.0
    }
  ]
}
```

## Response fields

- `formula` (string): maddrey_1978
- `formula_expression` (string): Exact expression used
- `pt_patient_sec` (number): Patient PT in seconds
- `pt_control_sec` (number): Control PT in seconds
- `bilirubin_mg_dl` (number): Normalized bilirubin in mg/dL
- `df` (number): Maddrey discriminant function, 1 decimal place
- `citation` (object): Gastroenterology 1978 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "df": 44.8,
  "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": "Maddrey WC, Boitnott JK, Bedine MS, Weber FL Jr, Mezey E, White RI Jr",
    "doi": "10.1016/0016-5085(78)90401-8",
    "id": "maddrey-1978",
    "source": "Gastroenterology. 1978;75(2):193-199",
    "title": "Corticosteroid therapy of alcoholic hepatitis"
  },
  "formula": "maddrey_1978",
  "formula_expression": "DF = 4.6 * (pt_patient_sec - pt_control_sec) + bilirubin_mg_dl",
  "bilirubin_mg_dl": 8.0,
  "pt_control_sec": 12.0,
  "pt_patient_sec": 20.0
}
```

## Errors

- HTTP 400 `invalid_prothrombin_time`: pt_patient_sec (8-120) and pt_control_sec (8-20) are 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_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object 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 `settle_failed`: Settlement failed; retry with the same PAYMENT-SIGNATURE shortly
- 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

- [MELD-Na](https://magentlab.com/docs/meld-na) — Compute OPTN/UNOS 2016 MELD and MELD-Na from creatinine, bilirubin, INR, sodium, and dialysis.
- [FIB-4](https://magentlab.com/docs/fib4) — Compute the FIB-4 fibrosis index from age, AST, ALT, and platelets.

## Also searched as

- Maddrey DF
- Maddrey's discriminant function
- discriminant function alcoholic hepatitis
- Maddrey score
- PT bilirubin DF

## 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.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign EIP-3009 with validBefore = now + accepts[0].maxTimeoutSeconds (600 seconds). That window starts when you sign and must cover wallet confirmation plus CDP verify and settle. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON echoing accepted, payload, and extensions when present).
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. Settlement happens before the tool runs. HTTP 503 settlement_uncertain or settle_failed: retry the same PAYMENT-SIGNATURE. Mint a new nonce only after a new HTTP 402.

## Guarantees

- Invalid query parameters return HTTP 400 before settlement. You are not charged.
- Settlement finishes before the tool executes. 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 not persisted. Request logs store path without query.