GI · LIVE

BUN/creatinine ratio

Compute the Richards 1990 blood urea nitrogen to creatinine ratio and whether that ratio is >= 36 (suggests upper gastrointestinal bleeding).

LIVE $0.005 USDC GET /api/calc/bun_creatinine_ratio

Markdown: /docs/bun-creatinine-ratio.md · Canonical: https://magentlab.com/docs/bun-creatinine-ratio

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

What it computes

Compute the Richards 1990 blood urea nitrogen to creatinine ratio and whether that ratio is >= 36 (suggests upper gastrointestinal bleeding).

When to use

When an agent needs the published Richards 1990 BUN/creatinine ratio and must not invent a lower-GI class, an endoscopy order, or Glasgow-Blatchford urea bands.

When not to use

• Not a medical device.
• Not a diagnosis. magent does not locate a gastrointestinal bleed and does not order endoscopy.
• A ratio >= 36 suggests upper gastrointestinal bleeding. A ratio < 36 is not helpful in locating the source; magent does not classify that as lower GI bleeding.
• Richards 1990: no patient with lower GI bleeding had a ratio >= 36; 38% of patients with upper GI bleeding had a ratio >= 36. Those figures are not returned in the JSON body.
• Not the Glasgow-Blatchford urea or BUN tables. This tool does not score Blatchford bands.

Formula

bun_creatinine_ratio = bun_mg_dl / creatinine_mg_dl

Citation

Title

Can the blood urea nitrogen/creatinine ratio distinguish upper from lower gastrointestinal bleeding?

Authors

Richards RJ, Donica MB, Grayer D

Source

J Clin Gastroenterol. 1990;12(5):500-504

DOI

10.1097/00004836-199010000-00004

Worked example

Also searched as

• BUN creatinine ratio
• BUN/Cr ratio
• blood urea nitrogen creatinine ratio
• Richards GI bleed ratio
• upper GI bleeding BUN creatinine
• BUN Cr localization
• azotemia GI bleed

Try

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

/api/calc/bun_creatinine_ratio?bun_mg_dl=36&creatinine_mg_dl=1

Full URL: https://api.magentlab.com/api/calc/bun_creatinine_ratio?bun_mg_dl=36&creatinine_mg_dl=1

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/bun_creatinine_ratio?bun_mg_dl=36&creatinine_mg_dl=1"

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/bun_creatinine_ratio 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": [
    {
      "bun_mg_dl": "36",
      "creatinine_mg_dl": "1"
    },
    {
      "bun_mg_dl": "36",
      "creatinine_mg_dl": "1"
    }
  ]
}

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/bun_creatinine_ratio",
  "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": "Richards RJ, Donica MB, Grayer D",
        "doi": "10.1097/00004836-199010000-00004",
        "id": "richards-1990",
        "pmid": "2229992",
        "source": "J Clin Gastroenterol. 1990;12(5):500-504",
        "title": "Can the blood urea nitrogen/creatinine ratio distinguish upper from lower gastrointestinal bleeding?"
      },
      "formula": "bun_creatinine_ratio",
      "formula_expression": "bun_creatinine_ratio = bun_mg_dl / creatinine_mg_dl",
      "creatinine_mg_dl": 1.0,
      "bun_mg_dl": 36.0,
      "bun_creatinine_ratio": 36.0,
      "suggests_upper_gi_bleeding": true
    },
    {
      "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": "Richards RJ, Donica MB, Grayer D",
        "doi": "10.1097/00004836-199010000-00004",
        "id": "richards-1990",
        "pmid": "2229992",
        "source": "J Clin Gastroenterol. 1990;12(5):500-504",
        "title": "Can the blood urea nitrogen/creatinine ratio distinguish upper from lower gastrointestinal bleeding?"
      },
      "formula": "bun_creatinine_ratio",
      "formula_expression": "bun_creatinine_ratio = bun_mg_dl / creatinine_mg_dl",
      "creatinine_mg_dl": 1.0,
      "bun_mg_dl": 36.0,
      "bun_creatinine_ratio": 36.0,
      "suggests_upper_gi_bleeding": true
    }
  ]
}

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": "Richards RJ, Donica MB, Grayer D",
    "doi": "10.1097/00004836-199010000-00004",
    "id": "richards-1990",
    "pmid": "2229992",
    "source": "J Clin Gastroenterol. 1990;12(5):500-504",
    "title": "Can the blood urea nitrogen/creatinine ratio distinguish upper from lower gastrointestinal bleeding?"
  },
  "formula": "bun_creatinine_ratio",
  "formula_expression": "bun_creatinine_ratio = bun_mg_dl / creatinine_mg_dl",
  "creatinine_mg_dl": 1.0,
  "bun_mg_dl": 36.0,
  "bun_creatinine_ratio": 36.0,
  "suggests_upper_gi_bleeding": true
}

Client errors (HTTP 400)

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

Related tools

• Glasgow-Blatchford score — Compute the Blatchford 2000 Glasgow-Blatchford score from urea, haemoglobin, systolic BP, heart rate, and four clinical flags.
• Oakland score — Sum the Oakland 2017 derivation-table weights for acute lower gastrointestinal bleeding and return safe_discharge (score ≤8) or not_safe (score >8).
• Rockall — Compute the Rockall 1996 complete (post-endoscopy) score from age, heart rate, systolic blood pressure, caller-assigned comorbidity, diagnosis, and stigmata of recent haemorrhage after acute upper gastrointestinal haemorrhage.

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.