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SAFE score

Compute the Sripongpun 2023 steatosis-associated fibrosis estimator (SAFE) from age, caller-supplied BMI, diabetes, AST, ALT, globulin in g/dL, and platelets.

LIVE $0.005 USDC GET /api/calc/safe

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

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

What it computes

Compute the Sripongpun 2023 steatosis-associated fibrosis estimator (SAFE) from age, caller-supplied BMI, diabetes, AST, ALT, globulin in g/dL, and platelets.

When to use

When an agent needs published Sripongpun 2023 SAFE arithmetic and must not invent FIB-4, NAFLD fibrosis, or BARD cutoffs or a biopsy result.

When not to use

• Not a medical device. Not a diagnosis and not a biopsy or fibrosis stage. SAFE bands are published cut-points, not histology.
• BMI is caller-supplied. magent does not compute BMI from height and weight in this tool. BMI above 40 is set to 40 in the formula only (Sripongpun 2023).
• Sripongpun 2023 SAFE only. Not FIB-4, not the NAFLD fibrosis score, and not the BARD score.
• Globulin must be in g/dL (total protein minus albumin). magent does not convert g/L or split protein and albumin.

Formula

SAFE = 2.97*age + 5.99*min(BMI, 40) + 154.85*ln(AST) - 58.23*ln(ALT) + 195.48*ln(globulin_g_dl) - 141.61*ln(platelets_10e9_l) + 62.85*(diabetes 0/1) - 75

Citation

Title

The steatosis-associated fibrosis estimator (SAFE) score: A tool to detect low-risk NAFLD in primary care

Authors

Sripongpun P, Kim WR, Mannalithara A, et al.

Source

Hepatology. 2023;77(1):256-267

DOI

10.1002/hep.32545

Worked example

Also searched as

• SAFE score
• steatosis-associated fibrosis estimator
• NAFLD SAFE
• Sripongpun SAFE
• SAFE NAFLD fibrosis
• globulin platelet NAFLD score

Try

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

/api/calc/safe?age=50&bmi_kg_m2=30&diabetes=false&ast_u_l=40&alt_u_l=40&globulin_g_dl=3&platelets_10e9_l=200

Full URL: https://api.magentlab.com/api/calc/safe?age=50&bmi_kg_m2=30&diabetes=false&ast_u_l=40&alt_u_l=40&globulin_g_dl=3&platelets_10e9_l=200

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/safe?age=50&bmi_kg_m2=30&diabetes=false&ast_u_l=40&alt_u_l=40&globulin_g_dl=3&platelets_10e9_l=200"

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/safe 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": [
    {
      "age": "50",
      "alt_u_l": "40",
      "ast_u_l": "40",
      "bmi_kg_m2": "30",
      "diabetes": "false",
      "globulin_g_dl": "3",
      "platelets_10e9_l": "200"
    },
    {
      "age": "50",
      "alt_u_l": "40",
      "ast_u_l": "40",
      "bmi_kg_m2": "30",
      "diabetes": "false",
      "globulin_g_dl": "3",
      "platelets_10e9_l": "200"
    }
  ]
}

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/safe",
  "items": [
    {
      "safe": 74.08,
      "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": "Sripongpun P, Kim WR, Mannalithara A, et al.",
        "doi": "10.1002/hep.32545",
        "id": "sripongpun-2023",
        "pmid": "35477908",
        "source": "Hepatology. 2023;77(1):256-267",
        "title": "The steatosis-associated fibrosis estimator (SAFE) score: A tool to detect low-risk NAFLD in primary care"
      },
      "formula": "safe",
      "formula_expression": "SAFE = 2.97*age + 5.99*min(BMI, 40) + 154.85*ln(AST) - 58.23*ln(ALT) + 195.48*ln(globulin_g_dl) - 141.61*ln(platelets_10e9_l) + 62.85*(diabetes 0/1) - 75",
      "age_years": 50,
      "ast_u_l": 40.0,
      "platelets_10e9_l": 200.0,
      "alt_u_l": 40.0,
      "diabetes": false,
      "bmi_kg_m2": 30.0,
      "bmi_used": 30.0,
      "globulin_g_dl": 3.0,
      "safe_band": "0_to_100"
    },
    {
      "safe": 74.08,
      "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": "Sripongpun P, Kim WR, Mannalithara A, et al.",
        "doi": "10.1002/hep.32545",
        "id": "sripongpun-2023",
        "pmid": "35477908",
        "source": "Hepatology. 2023;77(1):256-267",
        "title": "The steatosis-associated fibrosis estimator (SAFE) score: A tool to detect low-risk NAFLD in primary care"
      },
      "formula": "safe",
      "formula_expression": "SAFE = 2.97*age + 5.99*min(BMI, 40) + 154.85*ln(AST) - 58.23*ln(ALT) + 195.48*ln(globulin_g_dl) - 141.61*ln(platelets_10e9_l) + 62.85*(diabetes 0/1) - 75",
      "age_years": 50,
      "ast_u_l": 40.0,
      "platelets_10e9_l": 200.0,
      "alt_u_l": 40.0,
      "diabetes": false,
      "bmi_kg_m2": 30.0,
      "bmi_used": 30.0,
      "globulin_g_dl": 3.0,
      "safe_band": "0_to_100"
    }
  ]
}

Response

Example JSON

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

{
  "safe": 74.08,
  "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": "Sripongpun P, Kim WR, Mannalithara A, et al.",
    "doi": "10.1002/hep.32545",
    "id": "sripongpun-2023",
    "pmid": "35477908",
    "source": "Hepatology. 2023;77(1):256-267",
    "title": "The steatosis-associated fibrosis estimator (SAFE) score: A tool to detect low-risk NAFLD in primary care"
  },
  "formula": "safe",
  "formula_expression": "SAFE = 2.97*age + 5.99*min(BMI, 40) + 154.85*ln(AST) - 58.23*ln(ALT) + 195.48*ln(globulin_g_dl) - 141.61*ln(platelets_10e9_l) + 62.85*(diabetes 0/1) - 75",
  "age_years": 50,
  "ast_u_l": 40.0,
  "platelets_10e9_l": 200.0,
  "alt_u_l": 40.0,
  "diabetes": false,
  "bmi_kg_m2": 30.0,
  "bmi_used": 30.0,
  "globulin_g_dl": 3.0,
  "safe_band": "0_to_100"
}

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.
• NAFLD fibrosis score — Compute the Angulo 2007 NAFLD fibrosis score from age, BMI, IFG/diabetes, AST, ALT, platelets, and albumin.
• Fatty liver index — Compute the Bedogni 2006 fatty liver index from caller-supplied BMI, waist circumference, triglycerides, and GGT as a predictor of hepatic steatosis in the general population.
• BARD — Sum the Harrison 2008 BARD score (BMI ≥28, AST/ALT ≥0.8, diabetes) and return low (0–1) or high (2–4).

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.