# Rome II IBS criteria

Rome II IBS

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/rome_ii_ibs`
HTML: https://magentlab.com/docs/rome-ii-ibs
Markdown: https://magentlab.com/docs/rome-ii-ibs.md

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

## What it computes

Apply the Thompson 1999 Rome II IBS diagnostic criteria and return supporting_features_met (0-3) and whether the published IBS box holds (rome_ii_ibs).

## When to use

When an agent already has the four caller-assigned Rome II IBS flags as in Thompson 1999 and needs whether the published IBS box holds. magent does not examine the patient.

## When not to use

- Not a medical device.
- Not a diagnosis. magent does not diagnose irritable bowel syndrome.
- The caller assigns the four flags. magent does not examine the patient.
- This tool is the Thompson 1999 Rome II IBS diagnostic box only. Not Rome III (pain or discomfort at least 3 days per month), not Rome IV (pain at least 1 day per week), not Manning criteria, and not IBS-C/D/M subtype.

## Formula

```
rome_ii_ibs iff pain_or_discomfort_12_weeks_of_12_months and supporting_features_met >= 2; supporting_features_met counts relieved_with_defecation, onset_change_stool_frequency, and onset_change_stool_form (Thompson 1999 Rome II IBS diagnostic criteria)
```

## Citation

[Functional bowel disorders and functional abdominal pain](https://doi.org/10.1136/gut.45.2008.ii43)
Thompson WG, Longstreth GF, Drossman DA, Heaton KW, Irvine EJ, Müller-Lissner SA
Gut. 1999;45 Suppl 2:II43-II47
DOI: [10.1136/gut.45.2008.ii43](https://doi.org/10.1136/gut.45.2008.ii43)

## Worked example

### 12-week pain/discomfort and two supporting features

Given: `onset_change_stool_form=false, onset_change_stool_frequency=true, pain_or_discomfort_12_weeks_of_12_months=true, relieved_with_defecation=true`

1. At least 12 weeks of abdominal discomfort or pain in the preceding 12 months is true
2. Relieved with defecation and change in stool frequency are true; change in stool form is false (2 of 3)
3. rome_ii_ibs is true


### 12-week pain/discomfort with only one supporting feature

Given: `onset_change_stool_form=false, onset_change_stool_frequency=false, pain_or_discomfort_12_weeks_of_12_months=true, relieved_with_defecation=true`

1. The 12-week pain/discomfort flag holds
2. Only relieved with defecation is true (1 of 3)
3. rome_ii_ibs is false


## Also searched as

- Rome II IBS
- Rome II irritable bowel
- Thompson IBS criteria
- functional bowel IBS 1999
- IBS diagnostic criteria Rome II
- Thompson 1999 IBS
- irritable bowel syndrome Rome II
- Rome II IBS box

## Parameters

- `pain_or_discomfort_12_weeks_of_12_months` (boolean, required): At least 12 weeks (need not be consecutive) in the preceding 12 months of abdominal discomfort or pain (Thompson 1999). true or false as assigned by the caller. magent does not examine the patient.
- `relieved_with_defecation` (boolean, required): Abdominal discomfort or pain relieved with defecation (one of three supporting features; at least two required). true or false as assigned by the caller.
- `onset_change_stool_frequency` (boolean, required): Onset associated with a change in frequency of stool (one of three supporting features; at least two required). true or false as assigned by the caller.
- `onset_change_stool_form` (boolean, required): Onset associated with a change in form (appearance) of stool (one of three supporting features; at least two required). true or false as assigned by the caller.

## 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_ii_ibs`
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": [
    {
      "onset_change_stool_form": "false",
      "onset_change_stool_frequency": "true",
      "pain_or_discomfort_12_weeks_of_12_months": "true",
      "relieved_with_defecation": "true"
    },
    {
      "onset_change_stool_form": "false",
      "onset_change_stool_frequency": "true",
      "pain_or_discomfort_12_weeks_of_12_months": "true",
      "relieved_with_defecation": "true"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rome_ii_ibs",
  "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": "Thompson WG, Longstreth GF, Drossman DA, Heaton KW, Irvine EJ, Müller-Lissner SA",
        "doi": "10.1136/gut.45.2008.ii43",
        "id": "thompson-1999",
        "pmid": "10457044",
        "source": "Gut. 1999;45 Suppl 2:II43-II47",
        "title": "Functional bowel disorders and functional abdominal pain"
      },
      "formula": "rome_ii_ibs",
      "formula_expression": "rome_ii_ibs iff pain_or_discomfort_12_weeks_of_12_months and supporting_features_met >= 2; supporting_features_met counts relieved_with_defecation, onset_change_stool_frequency, and onset_change_stool_form (Thompson 1999 Rome II IBS diagnostic criteria)",
      "criteria": [
        {
          "factor": "pain_or_discomfort_12_weeks_of_12_months",
          "met": true
        },
        {
          "factor": "relieved_with_defecation",
          "met": true
        },
        {
          "factor": "onset_change_stool_frequency",
          "met": true
        },
        {
          "factor": "onset_change_stool_form",
          "met": false
        },
        {
          "value": 2,
          "factor": "supporting_features_ge_2",
          "met": true
        }
      ],
      "rome_ii_ibs": true,
      "supporting_features_met": 2
    },
    {
      "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": "Thompson WG, Longstreth GF, Drossman DA, Heaton KW, Irvine EJ, Müller-Lissner SA",
        "doi": "10.1136/gut.45.2008.ii43",
        "id": "thompson-1999",
        "pmid": "10457044",
        "source": "Gut. 1999;45 Suppl 2:II43-II47",
        "title": "Functional bowel disorders and functional abdominal pain"
      },
      "formula": "rome_ii_ibs",
      "formula_expression": "rome_ii_ibs iff pain_or_discomfort_12_weeks_of_12_months and supporting_features_met >= 2; supporting_features_met counts relieved_with_defecation, onset_change_stool_frequency, and onset_change_stool_form (Thompson 1999 Rome II IBS diagnostic criteria)",
      "criteria": [
        {
          "factor": "pain_or_discomfort_12_weeks_of_12_months",
          "met": true
        },
        {
          "factor": "relieved_with_defecation",
          "met": true
        },
        {
          "factor": "onset_change_stool_frequency",
          "met": true
        },
        {
          "factor": "onset_change_stool_form",
          "met": false
        },
        {
          "value": 2,
          "factor": "supporting_features_ge_2",
          "met": true
        }
      ],
      "rome_ii_ibs": true,
      "supporting_features_met": 2
    }
  ]
}
```

## Response fields

- `formula` (string): rome_ii_ibs
- `formula_expression` (string): Thompson 1999 Rome II IBS box: 12 weeks of pain/discomfort in 12 months and at least 2 of 3 supporting features
- `supporting_features_met` (integer): Count of true supporting features among relieved with defecation, change in stool frequency, and change in stool form (0-3)
- `rome_ii_ibs` (boolean): true only when the 12-week pain/discomfort flag and at least two supporting features all hold. Not a diagnosis.
- `criteria` (array): Per-factor rows with factor and met; supporting_features_ge_2 includes value 0-3
- `citation` (object): Thompson 1999 Gut 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": "Thompson WG, Longstreth GF, Drossman DA, Heaton KW, Irvine EJ, Müller-Lissner SA",
    "doi": "10.1136/gut.45.2008.ii43",
    "id": "thompson-1999",
    "pmid": "10457044",
    "source": "Gut. 1999;45 Suppl 2:II43-II47",
    "title": "Functional bowel disorders and functional abdominal pain"
  },
  "formula": "rome_ii_ibs",
  "formula_expression": "rome_ii_ibs iff pain_or_discomfort_12_weeks_of_12_months and supporting_features_met >= 2; supporting_features_met counts relieved_with_defecation, onset_change_stool_frequency, and onset_change_stool_form (Thompson 1999 Rome II IBS diagnostic criteria)",
  "criteria": [
    {
      "factor": "pain_or_discomfort_12_weeks_of_12_months",
      "met": true
    },
    {
      "factor": "relieved_with_defecation",
      "met": true
    },
    {
      "factor": "onset_change_stool_frequency",
      "met": true
    },
    {
      "factor": "onset_change_stool_form",
      "met": false
    },
    {
      "value": 2,
      "factor": "supporting_features_ge_2",
      "met": true
    }
  ],
  "rome_ii_ibs": true,
  "supporting_features_met": 2
}
```

## Errors

- 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 III IBS](https://magentlab.com/docs/rome-iii-ibs) — Apply the Longstreth 2006 Rome III IBS diagnostic criteria and return supporting_features_met (0-3) and whether the published IBS box holds (rome_iii_ibs).
- [Rome IV IBS](https://magentlab.com/docs/rome-iv-ibs) — Apply the Mearin 2016 Rome IV IBS diagnostic criteria and return supporting_features_met (0-3) and whether the published IBS box holds (rome_iv_ibs).

## 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.