Emergency · LIVE

Apfel 1999 PONV risk score

Apfel PONV score

Sum the four Apfel 1999 predictors for postoperative nausea and vomiting and return the published integer score (0-4).

LIVE $0.005 USDC GET /api/calc/apfel

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

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

What it computes

Sum the four Apfel 1999 predictors for postoperative nausea and vomiting and return the published integer score (0-4).

When to use

When an agent needs the published Apfel 1999 integer score and must not invent a prophylaxis order, a PONV diagnosis, or the paper's incidence percents.

When not to use

Not a medical device.
Not a prophylaxis order and not a diagnosis of PONV.
Apfel 1999 reported incidences by score. This tool returns the integer score without those percents.
The caller assigns sex, motion-sickness or PONV history, smoking status, and the postoperative opioid plan. magent does not take an anesthetic.

Formula

Apfel = female + history_motion_sickness_or_ponv + nonsmoker + postoperative_opioids; each 1 if true; max 4

Citation

Title: A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers.
Authors: Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N
Source: Anesthesiology. 1999;91(3):693-700
DOI: 10.1097/00000542-199909000-00022

Worked example

Male, no history, smoker, no postoperative opioids

Given: history_motion_sickness_or_ponv=falsenonsmoker=falsepostoperative_opioids=falsesex=male

Male → 0; history absent → 0; nonsmoker false → 0; postoperative opioids false → 0
Score = 0 (max 4); band 0

Female, history, nonsmoker, postoperative opioids

Given: history_motion_sickness_or_ponv=truenonsmoker=truepostoperative_opioids=truesex=female

Female → 1; history present → 1; nonsmoker → 1; postoperative opioids → 1
Score = 4 (max 4); band 4

Also searched as

Apfel score
Apfel PONV score
Apfel 1999
postoperative nausea and vomiting score
simplified PONV risk score
PONV predictors Apfel
motion sickness PONV score

Try

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

/api/calc/apfel?sex=male&history_motion_sickness_or_ponv=false&nonsmoker=false&postoperative_opioids=false

Full URL: https://api.magentlab.com/api/calc/apfel?sex=male&history_motion_sickness_or_ponv=false&nonsmoker=false&postoperative_opioids=false

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/apfel?sex=male&history_motion_sickness_or_ponv=false&nonsmoker=false&postoperative_opioids=false"

Parameters

Name	Type	Required	Description
`sex`	string	required · female, male	female or male (Apfel 1999). Female scores 1. Male scores 0. Assigned by the caller.
`history_motion_sickness_or_ponv`	boolean	required	History of motion sickness or postoperative nausea and vomiting (Apfel 1999). true or false as assigned by the caller. 1 point if true.
`nonsmoker`	boolean	required	Nonsmoking status (Apfel 1999). true scores 1. Smokers (false) score 0. Assigned by the caller.
`postoperative_opioids`	boolean	required	Postoperative opioids planned or given (Apfel 1999). true or false as assigned by the caller. 1 point if true. magent does not take an anesthetic.

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/apfel 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": [
    {
      "history_motion_sickness_or_ponv": "false",
      "nonsmoker": "false",
      "postoperative_opioids": "false",
      "sex": "male"
    },
    {
      "history_motion_sickness_or_ponv": "false",
      "nonsmoker": "false",
      "postoperative_opioids": "false",
      "sex": "male"
    }
  ]
}

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/apfel",
  "items": [
    {
      "band": "0",
      "components": [
        {
          "factor": "female",
          "points": 0,
          "present": false
        },
        {
          "factor": "history_motion_sickness_or_ponv",
          "points": 0,
          "present": false
        },
        {
          "factor": "nonsmoker",
          "points": 0,
          "present": false
        },
        {
          "factor": "postoperative_opioids",
          "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": "Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N",
        "doi": "10.1097/00000542-199909000-00022",
        "id": "apfel-1999",
        "pmid": "10485781",
        "source": "Anesthesiology. 1999;91(3):693-700",
        "title": "A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers."
      },
      "formula": "apfel",
      "formula_expression": "Apfel = female + history_motion_sickness_or_ponv + nonsmoker + postoperative_opioids; each 1 if true; max 4",
      "max_score": 4,
      "score": 0,
      "sex": "male"
    },
    {
      "band": "0",
      "components": [
        {
          "factor": "female",
          "points": 0,
          "present": false
        },
        {
          "factor": "history_motion_sickness_or_ponv",
          "points": 0,
          "present": false
        },
        {
          "factor": "nonsmoker",
          "points": 0,
          "present": false
        },
        {
          "factor": "postoperative_opioids",
          "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": "Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N",
        "doi": "10.1097/00000542-199909000-00022",
        "id": "apfel-1999",
        "pmid": "10485781",
        "source": "Anesthesiology. 1999;91(3):693-700",
        "title": "A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers."
      },
      "formula": "apfel",
      "formula_expression": "Apfel = female + history_motion_sickness_or_ponv + nonsmoker + postoperative_opioids; each 1 if true; max 4",
      "max_score": 4,
      "score": 0,
      "sex": "male"
    }
  ]
}

Response

Field	Type	Description
`formula`	string	apfel
`formula_expression`	string	Exact expression used
`score`	integer	Apfel 1999 points 0-4
`max_score`	integer	4
`band`	string	Published Apfel 1999 score stratum as a string: 0, 1, 2, 3, or 4. The integer score, not a prophylaxis order. Percents are not returned.
`sex`	string	female or male
`components`	array	Per-predictor points
`citation`	object	Apfel et al. Anesthesiology 1999 citation
`disclaimer`	string	Not-a-device notice

Example JSON

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

{
  "band": "0",
  "components": [
    {
      "factor": "female",
      "points": 0,
      "present": false
    },
    {
      "factor": "history_motion_sickness_or_ponv",
      "points": 0,
      "present": false
    },
    {
      "factor": "nonsmoker",
      "points": 0,
      "present": false
    },
    {
      "factor": "postoperative_opioids",
      "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": "Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N",
    "doi": "10.1097/00000542-199909000-00022",
    "id": "apfel-1999",
    "pmid": "10485781",
    "source": "Anesthesiology. 1999;91(3):693-700",
    "title": "A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers."
  },
  "formula": "apfel",
  "formula_expression": "Apfel = female + history_motion_sickness_or_ponv + nonsmoker + postoperative_opioids; each 1 if true; max 4",
  "max_score": 4,
  "score": 0,
  "sex": "male"
}

Client errors (HTTP 400)

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

HTTP	Code	When
400	`invalid_sex`	sex must be female or male Returned before settlement; you are not charged.
400	`invalid_flag`	boolean clinical flags must be true or false Returned before settlement; you are not charged.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

Surgical Apgar — Compute the Gawande 2007 intraoperative Surgical Apgar score from estimated blood loss, lowest mean arterial pressure, and lowest heart rate.
COWS — Sum the eleven Wesson 2003 Clinical Opiate Withdrawal Scale (COWS) items from caller-assigned appendix integers and return the published total (max 48) with the published severity cutoffs.

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.
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.