# NRS-2002 nutritional risk screening

NRS-2002

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/nrs_2002`
HTML: https://magentlab.com/docs/nrs-2002
Markdown: https://magentlab.com/docs/nrs-2002.md

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

## What it computes

Sum Kondrup 2003 NRS-2002 impaired nutritional status (0–3), disease severity (0–3), and 1 if age ≥70, and return whether the total is at nutritional risk (score ≥3).

## When to use

When an agent has caller-assigned Kondrup 2003 nutrition and severity grades and needs the published NRS-2002 total and at-risk flag, not a diet order, not NRI, and without recomputing BMI or weight-loss arithmetic.

## When not to use

- Not a medical device.
- Not a diet order. magent does not weigh the patient and does not compute BMI, percent weight loss, or food intake from measurements.
- Kondrup 2003 NRS-2002 for hospitalized adults. at_risk is true iff score ≥ 3. No other bands are returned.
- This is not NRI (Nutritional Risk Index).

## Formula

```
NRS-2002 = nutrition_status (0–3) + disease_severity (0–3) + 1 if age ≥ 70; max 7; at_risk if score ≥ 3
```

## Citation

[Nutritional risk screening (NRS 2002): a new method based on an analysis of controlled clinical trials](https://doi.org/10.1016/s0261-5614(02)00214-5)
Kondrup J, Rasmussen HH, Hamberg O, Stanga Z, Ad Hoc ESPEN Working Group
Clin Nutr. 2003;22(3):321-336
DOI: [10.1016/s0261-5614(02)00214-5](https://doi.org/10.1016/s0261-5614(02)00214-5)

## Worked example

### No impairment, age 50

Given: `age=50, disease_severity=0, nutrition_status=0`

1. nutrition_status 0 + disease_severity 0 + age 50 is not ≥70 → 0
2. Score = 0 (max 7); at_risk false


### Mild nutrition, mild severity, age 70

Given: `age=70, disease_severity=1, nutrition_status=1`

1. nutrition_status 1 + disease_severity 1 + age ≥70 → 1
2. Score = 3 (max 7); at_risk true


## Also searched as

- NRS-2002
- NRS 2002
- Nutritional risk screening
- Kondrup NRS
- ESPEN NRS-2002
- nutrition risk screening 2002
- NRS2002

## Parameters

- `nutrition_status` (integer, required): Caller-assigned Kondrup 2003 impaired nutritional status 0-3. If BMI, intake, and weight-loss grades differ, use the highest. 0 absent. 1 mild (weight loss >5% in 3 months or food intake 50-75% of requirement last week). 2 moderate (weight loss >5% in 2 months or BMI 18.5-20.5 plus impaired general condition or intake 25-60%). 3 severe (weight loss >5% in 1 month / >15% in 3 months or BMI <18.5 plus impaired general condition or intake 0-25%). magent does not weigh the patient or compute BMI, weight-loss, or intake.
- `disease_severity` (integer, required): Caller-assigned Kondrup 2003 disease severity 0-3. 0 absent (normal requirements). 1 mild (e.g. hip fracture; chronic illness with complications: cirrhosis, COPD, chronic hemodialysis, diabetes, oncology). 2 moderate (e.g. major abdominal surgery, stroke, severe pneumonia, hematologic malignancy). 3 severe (e.g. head injury, bone marrow transplant, ICU APACHE >10). magent does not assign the diagnosis.
- `age` (integer, required): Age in years (18-120). Kondrup 2003: add 1 point when age ≥70. Age 70 scores. Age 69 does not.

## 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.

Method: `POST /api/calc/nrs_2002`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: 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:

```json
{
  "items": [
    {
      "age": "50",
      "disease_severity": "0",
      "nutrition_status": "0"
    },
    {
      "age": "50",
      "disease_severity": "0",
      "nutrition_status": "0"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/nrs-2002

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/nrs_2002",
  "items": [
    {
      "components": [
        {
          "value": 0,
          "factor": "nutrition_status",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "disease_severity",
          "points": 0,
          "present": false
        },
        {
          "value": 50,
          "factor": "age_ge_70",
          "points": 0,
          "present": false
        }
      ],
      "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": "Kondrup J, Rasmussen HH, Hamberg O, Stanga Z, Ad Hoc ESPEN Working Group",
        "doi": "10.1016/s0261-5614(02)00214-5",
        "id": "kondrup-2003",
        "pmid": "12765680",
        "source": "Clin Nutr. 2003;22(3):321-336",
        "title": "Nutritional risk screening (NRS 2002): a new method based on an analysis of controlled clinical trials"
      },
      "formula": "nrs_2002",
      "formula_expression": "NRS-2002 = nutrition_status (0–3) + disease_severity (0–3) + 1 if age ≥ 70; max 7; at_risk if score ≥ 3",
      "age_years": 50,
      "max_score": 7,
      "score": 0,
      "at_risk": false,
      "disease_severity": 0,
      "nutrition_status": 0
    },
    {
      "components": [
        {
          "value": 0,
          "factor": "nutrition_status",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "disease_severity",
          "points": 0,
          "present": false
        },
        {
          "value": 50,
          "factor": "age_ge_70",
          "points": 0,
          "present": false
        }
      ],
      "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": "Kondrup J, Rasmussen HH, Hamberg O, Stanga Z, Ad Hoc ESPEN Working Group",
        "doi": "10.1016/s0261-5614(02)00214-5",
        "id": "kondrup-2003",
        "pmid": "12765680",
        "source": "Clin Nutr. 2003;22(3):321-336",
        "title": "Nutritional risk screening (NRS 2002): a new method based on an analysis of controlled clinical trials"
      },
      "formula": "nrs_2002",
      "formula_expression": "NRS-2002 = nutrition_status (0–3) + disease_severity (0–3) + 1 if age ≥ 70; max 7; at_risk if score ≥ 3",
      "age_years": 50,
      "max_score": 7,
      "score": 0,
      "at_risk": false,
      "disease_severity": 0,
      "nutrition_status": 0
    }
  ]
}
```

## Response fields

- `formula` (string): nrs_2002
- `formula_expression` (string): Exact expression used
- `score` (integer): NRS-2002 points 0-7
- `max_score` (integer): 7
- `at_risk` (boolean): true iff score ≥ 3 (Kondrup 2003 / ESPEN NRS-2002). Not a diet order. No other bands.
- `nutrition_status` (integer): Caller-assigned impaired nutritional status 0-3 used
- `disease_severity` (integer): Caller-assigned disease severity 0-3 used
- `age_years` (integer): Age used for the ≥70 point
- `components` (array): Per-item Kondrup 2003 points
- `citation` (object): Kondrup et al. Clin Nutr 2003 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "value": 0,
      "factor": "nutrition_status",
      "points": 0,
      "present": false
    },
    {
      "value": 0,
      "factor": "disease_severity",
      "points": 0,
      "present": false
    },
    {
      "value": 50,
      "factor": "age_ge_70",
      "points": 0,
      "present": false
    }
  ],
  "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": "Kondrup J, Rasmussen HH, Hamberg O, Stanga Z, Ad Hoc ESPEN Working Group",
    "doi": "10.1016/s0261-5614(02)00214-5",
    "id": "kondrup-2003",
    "pmid": "12765680",
    "source": "Clin Nutr. 2003;22(3):321-336",
    "title": "Nutritional risk screening (NRS 2002): a new method based on an analysis of controlled clinical trials"
  },
  "formula": "nrs_2002",
  "formula_expression": "NRS-2002 = nutrition_status (0–3) + disease_severity (0–3) + 1 if age ≥ 70; max 7; at_risk if score ≥ 3",
  "age_years": 50,
  "max_score": 7,
  "score": 0,
  "at_risk": false,
  "disease_severity": 0,
  "nutrition_status": 0
}
```

## Errors

- HTTP 400 `invalid_nrs_nutrition`: nutrition_status must be an integer 0, 1, 2, or 3 (Kondrup 2003 NRS-2002). Returned before settlement; you are not charged.
- HTTP 400 `invalid_nrs_severity`: disease_severity must be an integer 0, 1, 2, or 3 (Kondrup 2003 NRS-2002). Returned before settlement; you are not charged.
- HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

## Related tools

- [NRI](https://magentlab.com/docs/nri) — Apply the VA TPN Cooperative Study 1991 Nutritional Risk Index from caller-supplied albumin and current/usual weight.

## 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.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/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.