# VA TPN 1991 Nutritional Risk Index (NRI) Calculator

> VA TPN 1991 Nutritional Risk Index (NRI) Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Computes the Nutritional Risk Index (NRI) from serum albumin and weight data, and classifies malnutrition severity into four strata per the 1991 VA TPN NEJM criteria.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/nri
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/va-tpn-1991-nutritional-risk-index-nri-calculator-5b13b2c7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JSzxiIgj6zTx2w6al05v5

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability va-tpn-1991-nutritional-risk-index-nri-calculator-5b13b2c7
```

Example prompt: Calculate the NRI score for a patient whose serum albumin is 3.2 g/dL, current weight is 58 kg, and usual weight is 70 kg, and tell me which malnutrition stratum they fall into.

## When to prefer this

Use this endpoint when you need a quick, validated computation of the 1991 VA TPN Nutritional Risk Index specifically — not the GNRI (Geriatric Nutritional Risk Index) or PNI (Prognostic Nutritional Index). Choose this when you have serum albumin (in g/L or g/dL) plus current and usual weights, and need an NRI-based stratum per the NEJM 1991 criteria for clinical documentation or nutrition screening workflows.

## Known failure modes

- Missing required query params (current_weight_kg or usual_weight_kg) returns an error
- Providing both albumin_g_l and albumin_g_dl simultaneously causes a conflict error
- usual_weight_kg of 0 causes division by zero error
- Values outside valid ranges (albumin 10-60 g/L, weights 1-500 kg) may be rejected or produce unreliable output
- Payment not provided or insufficient results in x402 payment required response

## How this service works

VA TPN 1991 Nutritional Risk Index (NEJM): NRI = 1.519*albumin_g_l + 41.7*(current/usual weight). Malnourished if NRI <= 100. Strata: not_malnourished if NRI > 100; borderline_malnourished if 97.5 < NRI <= 100; mildly_malnourished if 83.5 <= NRI <= 97.5; severely_malnourished if NRI < 83.5. Does not cap current/usual at 1. Not a malnutrition diagnosis or TPN order. magent does not assay albumin or weigh the patient. Not GNRI or PNI.

## Output

Returns the computed NRI value (a continuous score using the formula 1.519 × albumin_g_l + 41.7 × (current_weight_kg / usual_weight_kg)) and a malnutrition stratum label: 'not_malnourished' (NRI > 100), 'borderline_malnourished' (97.5 < NRI ≤ 100), 'mildly_malnourished' (83.5 ≤ NRI ≤ 97.5), or 'severely_malnourished' (NRI < 83.5).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "current_weight_kg",
      "usual_weight_kg"
     ],
     "properties": {
      "albumin_g_l": {
       "type": "number",
       "description": "Serum albumin in g/L (10-60). Provide this or albumin_g_dl, not both. VA TPN 1991 NRI uses g/L. magent does not assay albumin."
      },
      "albumin_g_dl": {
       "type": "number",
       "description": "Serum albumin in g/dL (1-6). Converted as g/L = g/dL × 10. Provide this or albumin_g_l, not both."
      },
      "usual_weight_kg": {
       "type": "number",
       "description": "Usual weight in kg (1-500). Must be greater than 0. magent does not weigh the patient."
      },
      "current_weight_kg": {
       "type": "number",
       "description": "Current weight in kg (1-500). Not capped at usual weight. magent does not weigh the patient."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/va-tpn-1991-nutritional-risk-index-nri-calculator-5b13b2c7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)