Emergency · LIVE

Nutritional Risk Index (NRI)

NRI

Apply the VA TPN Cooperative Study 1991 Nutritional Risk Index from caller-supplied albumin and current/usual weight.

LIVE $0.005 USDC GET /api/calc/nri

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

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

What it computes

Apply the VA TPN Cooperative Study 1991 Nutritional Risk Index from caller-supplied albumin and current/usual weight.

When to use

When an agent has serum albumin and current and usual weights and needs the published VA TPN 1991 NRI screening and strata, not GNRI, not PNI, and not a malnutrition diagnosis or TPN order.

When not to use

• Not a medical device. magent does not assay albumin or weigh the patient.
• Not a malnutrition diagnosis or TPN order.
• VA TPN 1991 NRI only. This is not GNRI and not PNI.

Formula

NRI = 1.519 × albumin_g_l + 0.417 × (current_weight_kg / usual_weight_kg) × 100

Citation

Title

Perioperative total parenteral nutrition in surgical patients

Authors

The Veterans Affairs Total Parenteral Nutrition Cooperative Study Group

Source

N Engl J Med. 1991;325(8):525-532

DOI

10.1056/NEJM199108223250801

Worked example

Also searched as

• Nutritional Risk Index
• NRI
• VA TPN NRI
• Veterans Affairs NRI
• perioperative TPN nutrition index
• serum albumin usual weight NRI
• NEJM 1991 NRI

Try

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

/api/calc/nri?albumin_g_l=40&current_weight_kg=70&usual_weight_kg=70

Full URL: https://api.magentlab.com/api/calc/nri?albumin_g_l=40&current_weight_kg=70&usual_weight_kg=70

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/nri?albumin_g_l=40&current_weight_kg=70&usual_weight_kg=70"

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/nri 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": [
    {
      "albumin_g_l": "40",
      "current_weight_kg": "70",
      "usual_weight_kg": "70"
    },
    {
      "albumin_g_l": "40",
      "current_weight_kg": "70",
      "usual_weight_kg": "70"
    }
  ]
}

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/nri",
  "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": "The Veterans Affairs Total Parenteral Nutrition Cooperative Study Group",
        "doi": "10.1056/NEJM199108223250801",
        "id": "va-tpn-1991",
        "pmid": "1906163",
        "source": "N Engl J Med. 1991;325(8):525-532",
        "title": "Perioperative total parenteral nutrition in surgical patients"
      },
      "formula": "nri",
      "formula_expression": "NRI = 1.519 × albumin_g_l + 0.417 × (current_weight_kg / usual_weight_kg) × 100",
      "albumin_g_l": 40.0,
      "current_weight_kg": 70.0,
      "nri": 102.5,
      "screening": "not_malnourished",
      "stratification": "not_malnourished",
      "usual_weight_kg": 70.0
    },
    {
      "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": "The Veterans Affairs Total Parenteral Nutrition Cooperative Study Group",
        "doi": "10.1056/NEJM199108223250801",
        "id": "va-tpn-1991",
        "pmid": "1906163",
        "source": "N Engl J Med. 1991;325(8):525-532",
        "title": "Perioperative total parenteral nutrition in surgical patients"
      },
      "formula": "nri",
      "formula_expression": "NRI = 1.519 × albumin_g_l + 0.417 × (current_weight_kg / usual_weight_kg) × 100",
      "albumin_g_l": 40.0,
      "current_weight_kg": 70.0,
      "nri": 102.5,
      "screening": "not_malnourished",
      "stratification": "not_malnourished",
      "usual_weight_kg": 70.0
    }
  ]
}

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": "The Veterans Affairs Total Parenteral Nutrition Cooperative Study Group",
    "doi": "10.1056/NEJM199108223250801",
    "id": "va-tpn-1991",
    "pmid": "1906163",
    "source": "N Engl J Med. 1991;325(8):525-532",
    "title": "Perioperative total parenteral nutrition in surgical patients"
  },
  "formula": "nri",
  "formula_expression": "NRI = 1.519 × albumin_g_l + 0.417 × (current_weight_kg / usual_weight_kg) × 100",
  "albumin_g_l": 40.0,
  "current_weight_kg": 70.0,
  "nri": 102.5,
  "screening": "not_malnourished",
  "stratification": "not_malnourished",
  "usual_weight_kg": 70.0
}

Client errors (HTTP 400)

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

Related tools

• Charlson CCI — Sum the nineteen Charlson 1987 original comorbidity weights and return the published 1-year mortality group.
• Surgical Apgar — Compute the Gawande 2007 intraoperative Surgical Apgar score from estimated blood loss, lowest mean arterial pressure, and lowest heart rate.

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.