LIVE

APRI (AST to platelet ratio index)

APRI

Compute the AST to platelet ratio index (APRI) from AST, laboratory AST ULN, and platelet count.

LIVE $0.005 USDC GET /api/calc/apri

Markdown: /docs/apri.md · Canonical: https://magentlab.com/docs/apri

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

What it computes

Compute the AST to platelet ratio index (APRI) from AST, laboratory AST ULN, and platelet count.

When to use

When an agent needs Wai 2003 APRI arithmetic and must not invent FIB-4, a NAFLD fibrosis score, or an AST ULN of 40.

When not to use

• Not a diagnosis. Wai 2003 cut-offs are published training-set ROC coordinates, not a biopsy.
• This is not FIB-4 and not the NAFLD fibrosis score.
• Derived in chronic hepatitis C; magent does not re-derive cut-offs for other diseases.
• ast_uln_u_l is required caller input; magent does not assume an AST ULN of 40 U/L.

Formula

APRI = ((AST / AST_ULN) / platelet_count_10e9_L) * 100

Citation

Title

A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C

Authors

Wai CT, Greenson JK, Fontana RJ, et al.

Source

Hepatology. 2003;38(2):518-526

DOI

10.1053/jhep.2003.50346

Worked example

Also searched as

• AST to platelet ratio index
• AST/platelet ratio
• Wai APRI
• aspartate aminotransferase platelet ratio
• APRI score
• APRI hepatitis C

Try

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

/api/calc/apri?ast_u_l=90&ast_uln_u_l=45&platelets_10e9_l=120

Full URL: https://api.magentlab.com/api/calc/apri?ast_u_l=90&ast_uln_u_l=45&platelets_10e9_l=120

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/apri?ast_u_l=90&ast_uln_u_l=45&platelets_10e9_l=120"

Parameters

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.

POST /api/calc/apri Max 25 unit_amount * n 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 (fixture)

{
  "items": [
    {
      "ast_u_l": "90",
      "ast_uln_u_l": "45",
      "platelets_10e9_l": "120"
    },
    {
      "ast_u_l": "90",
      "ast_uln_u_l": "45",
      "platelets_10e9_l": "120"
    }
  ]
}

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/apri",
  "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": "Wai CT, Greenson JK, Fontana RJ, et al.",
        "doi": "10.1053/jhep.2003.50346",
        "id": "wai-2003",
        "source": "Hepatology. 2003;38(2):518-526",
        "title": "A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C"
      },
      "formula": "apri",
      "formula_expression": "APRI = ((AST / AST_ULN) / platelet_count_10e9_L) * 100",
      "apri": 1.67,
      "ast_u_l": 90.0,
      "ast_uln_u_l": 45.0,
      "platelets_10e9_l": 120.0,
      "wai_cirrhosis_band": "indeterminate",
      "wai_fibrosis_band": "high"
    },
    {
      "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": "Wai CT, Greenson JK, Fontana RJ, et al.",
        "doi": "10.1053/jhep.2003.50346",
        "id": "wai-2003",
        "source": "Hepatology. 2003;38(2):518-526",
        "title": "A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C"
      },
      "formula": "apri",
      "formula_expression": "APRI = ((AST / AST_ULN) / platelet_count_10e9_L) * 100",
      "apri": 1.67,
      "ast_u_l": 90.0,
      "ast_uln_u_l": 45.0,
      "platelets_10e9_l": 120.0,
      "wai_cirrhosis_band": "indeterminate",
      "wai_fibrosis_band": "high"
    }
  ]
}

Response

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": "Wai CT, Greenson JK, Fontana RJ, et al.",
    "doi": "10.1053/jhep.2003.50346",
    "id": "wai-2003",
    "source": "Hepatology. 2003;38(2):518-526",
    "title": "A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C"
  },
  "formula": "apri",
  "formula_expression": "APRI = ((AST / AST_ULN) / platelet_count_10e9_L) * 100",
  "apri": 1.67,
  "ast_u_l": 90.0,
  "ast_uln_u_l": 45.0,
  "platelets_10e9_l": 120.0,
  "wai_cirrhosis_band": "indeterminate",
  "wai_fibrosis_band": "high"
}

Client errors (HTTP 400)

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

Related tools

• FIB-4 — Compute the FIB-4 fibrosis index from age, AST, ALT, and platelets.

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. 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

• Invalid query parameters return HTTP 400 before settlement. You are not charged.
• Settlement finishes before the tool executes (paymentFlow upfront). 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.