# Rome IV chronic nausea vomiting syndrome

Rome IV CNVS

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/rome_iv_cnvs`
HTML: https://magentlab.com/docs/rome-iv-cnvs
Markdown: https://magentlab.com/docs/rome-iv-cnvs.md

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

## What it computes

Apply the Stanghellini 2016 Rome IV chronic nausea vomiting syndrome (CNVS, B3a) diagnostic criteria and return whether the published CNVS box holds (rome_iv_cnvs).

## When to use

When an agent already has the five caller-assigned Stanghellini 2016 Rome IV chronic nausea vomiting syndrome flags and needs whether the published CNVS box holds. magent does not take a history or read endoscopy.

## When not to use

- Not a medical device.
- Not a diagnosis. magent does not diagnose chronic nausea vomiting syndrome.
- The caller assigns the five flags. magent does not take a history or read endoscopy.
- This tool is Stanghellini 2016 Rome IV chronic nausea vomiting syndrome (B3a) only. Criterion 1 (bothersome nausea at least 1 day per week and/or one or more vomiting episodes per week) is one caller flag, not two. Not cyclic vomiting syndrome (CVS). Not cannabinoid hyperemesis syndrome (CHS). Not rumination.

## Formula

```
rome_iv_cnvs iff bothersome_nausea_or_vomiting_weekly and self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded and no_organic_systemic_metabolic_explanation and fulfilled_last_3_months and onset_at_least_6_months (Stanghellini 2016 Rome IV chronic nausea vomiting syndrome)
```

## Citation

[Gastroduodenal Disorders](https://doi.org/10.1053/j.gastro.2016.02.011)
Stanghellini V, Chan FKL, Hasler WL, Malagelada JR, Suzuki H, Tack J, Talley NJ
Gastroenterology. 2016;150(6):1380-1392
DOI: [10.1053/j.gastro.2016.02.011](https://doi.org/10.1053/j.gastro.2016.02.011)

## Worked example

### All five required flags

Given: `bothersome_nausea_or_vomiting_weekly=true, fulfilled_last_3_months=true, no_organic_systemic_metabolic_explanation=true, onset_at_least_6_months=true, self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded=true`

1. Bothersome nausea at least 1 day per week and/or one or more vomiting episodes per week is true as one flag
2. Self-induced vomiting, eating disorders, regurgitation, and rumination are excluded
3. No organic, systemic, or metabolic explanation including at upper endoscopy is true
4. Criteria fulfilled for the last 3 months and onset at least 6 months prior are true
5. rome_iv_cnvs is true


### Four required flags without 6-month onset

Given: `bothersome_nausea_or_vomiting_weekly=true, fulfilled_last_3_months=true, no_organic_systemic_metabolic_explanation=true, onset_at_least_6_months=false, self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded=true`

1. Four required flags hold
2. Onset at least 6 months prior is false
3. rome_iv_cnvs is false


## Also searched as

- Rome IV CNVS
- Rome IV chronic nausea vomiting syndrome
- Stanghellini 2016 CNVS
- chronic nausea vomiting syndrome Rome IV
- Rome IV B3a CNVS
- gastroduodenal CNVS
- chronic nausea and vomiting syndrome
- Rome IV chronic nausea and vomiting

## Parameters

- `bothersome_nausea_or_vomiting_weekly` (boolean, required): Bothersome (severe enough to impact usual activities) nausea at least 1 day per week and/or one or more vomiting episodes per week (Stanghellini 2016 Rome IV CNVS B3a). One caller flag covering nausea and/or vomiting. true or false as assigned by the caller. magent does not take a history.
- `self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded` (boolean, required): Self-induced vomiting, eating disorders, regurgitation, and rumination have been excluded (Stanghellini 2016). true or false as assigned by the caller. magent does not take a history.
- `no_organic_systemic_metabolic_explanation` (boolean, required): No evidence of organic, systemic, or metabolic disease likely to explain the symptoms on routine investigations including at upper endoscopy, as assigned (Stanghellini 2016). true or false as assigned by the caller. magent does not read endoscopy.
- `fulfilled_last_3_months` (boolean, required): Criteria fulfilled for the last 3 months, as assigned (Stanghellini 2016). true or false as assigned by the caller. magent does not take a history.
- `onset_at_least_6_months` (boolean, required): Symptom onset at least 6 months prior to diagnosis, as assigned (Stanghellini 2016). true or false as assigned by the caller. magent does not take a history.

## 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/rome_iv_cnvs`
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": [
    {
      "bothersome_nausea_or_vomiting_weekly": "true",
      "fulfilled_last_3_months": "true",
      "no_organic_systemic_metabolic_explanation": "true",
      "onset_at_least_6_months": "true",
      "self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded": "true"
    },
    {
      "bothersome_nausea_or_vomiting_weekly": "true",
      "fulfilled_last_3_months": "true",
      "no_organic_systemic_metabolic_explanation": "true",
      "onset_at_least_6_months": "true",
      "self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded": "true"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/rome-iv-cnvs

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rome_iv_cnvs",
  "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": "Stanghellini V, Chan FKL, Hasler WL, Malagelada JR, Suzuki H, Tack J, Talley NJ",
        "doi": "10.1053/j.gastro.2016.02.011",
        "id": "stanghellini-2016",
        "pmid": "27147122",
        "source": "Gastroenterology. 2016;150(6):1380-1392",
        "title": "Gastroduodenal Disorders"
      },
      "formula": "rome_iv_cnvs",
      "formula_expression": "rome_iv_cnvs iff bothersome_nausea_or_vomiting_weekly and self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded and no_organic_systemic_metabolic_explanation and fulfilled_last_3_months and onset_at_least_6_months (Stanghellini 2016 Rome IV chronic nausea vomiting syndrome)",
      "criteria": [
        {
          "factor": "bothersome_nausea_or_vomiting_weekly",
          "met": true
        },
        {
          "factor": "self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded",
          "met": true
        },
        {
          "factor": "no_organic_systemic_metabolic_explanation",
          "met": true
        },
        {
          "factor": "fulfilled_last_3_months",
          "met": true
        },
        {
          "factor": "onset_at_least_6_months",
          "met": true
        }
      ],
      "rome_iv_cnvs": 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": "Stanghellini V, Chan FKL, Hasler WL, Malagelada JR, Suzuki H, Tack J, Talley NJ",
        "doi": "10.1053/j.gastro.2016.02.011",
        "id": "stanghellini-2016",
        "pmid": "27147122",
        "source": "Gastroenterology. 2016;150(6):1380-1392",
        "title": "Gastroduodenal Disorders"
      },
      "formula": "rome_iv_cnvs",
      "formula_expression": "rome_iv_cnvs iff bothersome_nausea_or_vomiting_weekly and self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded and no_organic_systemic_metabolic_explanation and fulfilled_last_3_months and onset_at_least_6_months (Stanghellini 2016 Rome IV chronic nausea vomiting syndrome)",
      "criteria": [
        {
          "factor": "bothersome_nausea_or_vomiting_weekly",
          "met": true
        },
        {
          "factor": "self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded",
          "met": true
        },
        {
          "factor": "no_organic_systemic_metabolic_explanation",
          "met": true
        },
        {
          "factor": "fulfilled_last_3_months",
          "met": true
        },
        {
          "factor": "onset_at_least_6_months",
          "met": true
        }
      ],
      "rome_iv_cnvs": true
    }
  ]
}
```

## Response fields

- `formula` (string): rome_iv_cnvs
- `formula_expression` (string): Stanghellini 2016 Rome IV chronic nausea vomiting syndrome B3a: bothersome nausea at least 1 day per week and/or one or more vomiting episodes per week as one flag, self-induced vomiting eating disorders regurgitation and rumination excluded, no organic systemic or metabolic explanation including at upper endoscopy, last-3-months criteria, and 6-month onset
- `rome_iv_cnvs` (boolean): true only when all five required flags hold. Not a diagnosis.
- `criteria` (array): Per-factor rows with factor and met for the five required flags
- `citation` (object): Stanghellini 2016 Gastroenterology citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "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": "Stanghellini V, Chan FKL, Hasler WL, Malagelada JR, Suzuki H, Tack J, Talley NJ",
    "doi": "10.1053/j.gastro.2016.02.011",
    "id": "stanghellini-2016",
    "pmid": "27147122",
    "source": "Gastroenterology. 2016;150(6):1380-1392",
    "title": "Gastroduodenal Disorders"
  },
  "formula": "rome_iv_cnvs",
  "formula_expression": "rome_iv_cnvs iff bothersome_nausea_or_vomiting_weekly and self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded and no_organic_systemic_metabolic_explanation and fulfilled_last_3_months and onset_at_least_6_months (Stanghellini 2016 Rome IV chronic nausea vomiting syndrome)",
  "criteria": [
    {
      "factor": "bothersome_nausea_or_vomiting_weekly",
      "met": true
    },
    {
      "factor": "self_induced_vomiting_eating_disorders_regurgitation_rumination_excluded",
      "met": true
    },
    {
      "factor": "no_organic_systemic_metabolic_explanation",
      "met": true
    },
    {
      "factor": "fulfilled_last_3_months",
      "met": true
    },
    {
      "factor": "onset_at_least_6_months",
      "met": true
    }
  ],
  "rome_iv_cnvs": true
}
```

## Errors

- HTTP 400 `invalid_rome_iv_cnvs`: Rome IV chronic nausea vomiting needs the Stanghellini 2016 gastroduodenal CNVS flags. Returned before settlement; you are not charged.
- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false 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

- [Rome IV CVS](https://magentlab.com/docs/rome-iv-cvs) — Apply the Stanghellini 2016 Rome IV adult cyclic vomiting syndrome B3b diagnostic criteria and return whether the published CVS box holds (rome_iv_cvs) plus the supportive migraine_history flag.
- [Rome IV CHS](https://magentlab.com/docs/rome-iv-chs) — Apply the Stanghellini 2016 Rome IV cannabinoid hyperemesis syndrome diagnostic criteria and return whether the published CHS box holds (rome_iv_chs) plus the supportive pathologic_bathing flag.

## 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.