Liver · LIVE

R factor

Compute the Bénichou 1990 / CIOMS R ratio from ALT, ALP, and their laboratory upper limits of normal, then classify hepatocellular (R ≥ 5), cholestatic (R ≤ 2), or mixed (2 < R < 5).

LIVE $0.005 USDC GET /api/calc/r_factor

Markdown: /docs/r-factor.md · Canonical: https://magentlab.com/docs/r-factor

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

What it computes

Compute the Bénichou 1990 / CIOMS R ratio from ALT, ALP, and their laboratory upper limits of normal, then classify hepatocellular (R ≥ 5), cholestatic (R ≤ 2), or mixed (2 < R < 5).

When to use

When an agent needs the published CIOMS enzyme pattern from ALT and ALP and must not invent a RUCAM causality score or a DILI diagnosis.

When not to use

• Not a medical device. Not a DILI diagnosis or causality assessment.
• magent does not assay enzymes. Caller supplies ALT, ALP, and laboratory ULNs.
• R is the enzyme pattern only (hepatocellular, cholestatic, or mixed). magent does not compute RUCAM causality points.

Formula

R = (ALT / ALT_ULN) / (ALP / ALP_ULN)

Citation

Title

Criteria of drug-induced liver disorders. Report of an international consensus meeting

Authors

Bénichou C

Source

J Hepatol. 1990;11(2):272-276

DOI

10.1016/0168-8278(90)90124-A

Worked example

Also searched as

• R ratio
• R factor
• CIOMS R
• ALT ALP ratio
• hepatocellular cholestatic mixed
• Bénichou R factor
• drug-induced liver injury pattern
• enzyme pattern R

Try

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

/api/calc/r_factor?alt_u_l=200&alt_uln_u_l=40&alp_u_l=100&alp_uln_u_l=100

Full URL: https://api.magentlab.com/api/calc/r_factor?alt_u_l=200&alt_uln_u_l=40&alp_u_l=100&alp_uln_u_l=100

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/r_factor?alt_u_l=200&alt_uln_u_l=40&alp_u_l=100&alp_uln_u_l=100"

Parameters

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/r_factor 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": [
    {
      "alp_u_l": "100",
      "alp_uln_u_l": "100",
      "alt_u_l": "200",
      "alt_uln_u_l": "40"
    },
    {
      "alp_u_l": "100",
      "alp_uln_u_l": "100",
      "alt_u_l": "200",
      "alt_uln_u_l": "40"
    }
  ]
}

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/r_factor",
  "items": [
    {
      "pattern": "hepatocellular",
      "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": "Bénichou C",
        "doi": "10.1016/0168-8278(90)90124-A",
        "id": "benichou-1990",
        "pmid": "2254635",
        "source": "J Hepatol. 1990;11(2):272-276",
        "title": "Criteria of drug-induced liver disorders. Report of an international consensus meeting"
      },
      "formula": "r_factor",
      "formula_expression": "R = (ALT / ALT_ULN) / (ALP / ALP_ULN)",
      "alt_u_l": 200.0,
      "alp_u_l": 100.0,
      "alp_uln_u_l": 100.0,
      "alt_uln_u_l": 40.0,
      "r_ratio": 5.0
    },
    {
      "pattern": "hepatocellular",
      "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": "Bénichou C",
        "doi": "10.1016/0168-8278(90)90124-A",
        "id": "benichou-1990",
        "pmid": "2254635",
        "source": "J Hepatol. 1990;11(2):272-276",
        "title": "Criteria of drug-induced liver disorders. Report of an international consensus meeting"
      },
      "formula": "r_factor",
      "formula_expression": "R = (ALT / ALT_ULN) / (ALP / ALP_ULN)",
      "alt_u_l": 200.0,
      "alp_u_l": 100.0,
      "alp_uln_u_l": 100.0,
      "alt_uln_u_l": 40.0,
      "r_ratio": 5.0
    }
  ]
}

Response

Example JSON

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

{
  "pattern": "hepatocellular",
  "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": "Bénichou C",
    "doi": "10.1016/0168-8278(90)90124-A",
    "id": "benichou-1990",
    "pmid": "2254635",
    "source": "J Hepatol. 1990;11(2):272-276",
    "title": "Criteria of drug-induced liver disorders. Report of an international consensus meeting"
  },
  "formula": "r_factor",
  "formula_expression": "R = (ALT / ALT_ULN) / (ALP / ALP_ULN)",
  "alt_u_l": 200.0,
  "alp_u_l": 100.0,
  "alp_uln_u_l": 100.0,
  "alt_uln_u_l": 40.0,
  "r_ratio": 5.0
}

Client errors (HTTP 400)

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

Related tools

• ALBI — Compute the Johnson 2015 albumin-bilirubin (ALBI) linear predictor and grade from total bilirubin and albumin.
• Child–Pugh — Compute the Child–Turcotte–Pugh cirrhosis severity score from bilirubin, albumin, INR, encephalopathy, and ascites.
• FIB-4 — Compute the FIB-4 fibrosis index from age, AST, ALT, and platelets.

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.