# Rome IV H2b child IBS

Rome IV child IBS

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

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

## What it computes

Apply the Hyams 2016 Rome IV H2b child/adolescent IBS diagnostic criteria and return stool_features_met (0-3) and whether the published H2b box holds (rome_iv_child_ibs).

## When to use

When an agent already has the caller-assigned Hyams 2016 Rome IV H2b flags (pain at least 4 days per month, three stool features, constipation-pain flag, not another condition, and 2-month duration) and needs whether the published child 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 seven flags, including pain_does_not_resolve_with_constipation_treatment (true if there is no constipation, or if pain persists after treating constipation). magent does not examine the patient or treat constipation.
- This tool is Hyams 2016 Rome IV H2b child/adolescent IBS only. Not adult Rome IV IBS (Mearin 2016). Not child functional constipation. IBS-C/D/M/U subtypes are copy-only; this tool does not parse them.

## Formula

```
rome_iv_child_ibs iff abdominal_pain_at_least_4_days_per_month and stool_features_met >= 1 and pain_does_not_resolve_with_constipation_treatment and not_explained_by_another_condition and fulfilled_at_least_2_months; stool_features_met counts related_to_defecation, change_in_stool_frequency, and change_in_stool_form (Hyams 2016 Rome IV H2b child/adolescent IBS)
```

## Citation

[Childhood Functional Gastrointestinal Disorders: Child/Adolescent](https://doi.org/10.1053/j.gastro.2016.02.015)
Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M
Gastroenterology. 2016;150(6):1456-1468
DOI: [10.1053/j.gastro.2016.02.015](https://doi.org/10.1053/j.gastro.2016.02.015)

## Worked example

### Pain, two stool features, constipation-pain flag, and duration

Given: `abdominal_pain_at_least_4_days_per_month=true, change_in_stool_form=false, change_in_stool_frequency=true, fulfilled_at_least_2_months=true, not_explained_by_another_condition=true, pain_does_not_resolve_with_constipation_treatment=true, related_to_defecation=true`

1. Abdominal pain at least 4 days per month is true
2. Related to defecation and change in stool frequency are true; change in stool form is false (2 of 3)
3. Pain does not resolve with constipation treatment is true
4. Not explained by another condition is true
5. Fulfilled at least 2 months is true
6. rome_iv_child_ibs is true


### Worked example without the constipation-pain flag

Given: `abdominal_pain_at_least_4_days_per_month=true, change_in_stool_form=false, change_in_stool_frequency=true, fulfilled_at_least_2_months=true, not_explained_by_another_condition=true, pain_does_not_resolve_with_constipation_treatment=false, related_to_defecation=true`

1. Abdominal pain at least 4 days per month and two stool features hold
2. Pain does not resolve with constipation treatment is false
3. rome_iv_child_ibs is false


## Also searched as

- Rome IV child IBS
- Hyams 2016 child IBS
- Rome IV H2b
- pediatric irritable bowel
- childhood IBS criteria
- child adolescent IBS
- H2b IBS
- Rome IV pediatric IBS
- irritable bowel child Rome IV
- pediatric IBS Hyams 2016

## Parameters

- `abdominal_pain_at_least_4_days_per_month` (boolean, required): Abdominal pain at least 4 days per month, as assigned (Hyams 2016 Rome IV H2b). true or false as assigned by the caller. magent does not examine the patient.
- `related_to_defecation` (boolean, required): Pain related to defecation (one of three stool features; at least one required). true or false as assigned by the caller. magent does not examine the patient.
- `change_in_stool_frequency` (boolean, required): Pain associated with a change in frequency of stool (one of three stool features; at least one required). true or false as assigned by the caller. magent does not examine the patient.
- `change_in_stool_form` (boolean, required): Pain associated with a change in form (appearance) of stool (one of three stool features; at least one required). true or false as assigned by the caller. magent does not examine the patient.
- `pain_does_not_resolve_with_constipation_treatment` (boolean, required): Pain does not resolve with resolution of the constipation, as assigned (Hyams 2016 Rome IV H2b item 2). Assign true if there is no constipation, or if pain persists after treating constipation. true or false as assigned by the caller. magent does not treat constipation or examine the patient.
- `not_explained_by_another_condition` (boolean, required): After appropriate evaluation, the symptoms cannot be fully explained by another medical condition, as assigned (Hyams 2016 Rome IV H2b). true or false as assigned by the caller. magent does not examine the patient.
- `fulfilled_at_least_2_months` (boolean, required): Criteria fulfilled for at least 2 months, as assigned (Hyams 2016 Rome IV H2b). 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_child_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": [
    {
      "abdominal_pain_at_least_4_days_per_month": "true",
      "change_in_stool_form": "false",
      "change_in_stool_frequency": "true",
      "fulfilled_at_least_2_months": "true",
      "not_explained_by_another_condition": "true",
      "pain_does_not_resolve_with_constipation_treatment": "true",
      "related_to_defecation": "true"
    },
    {
      "abdominal_pain_at_least_4_days_per_month": "true",
      "change_in_stool_form": "false",
      "change_in_stool_frequency": "true",
      "fulfilled_at_least_2_months": "true",
      "not_explained_by_another_condition": "true",
      "pain_does_not_resolve_with_constipation_treatment": "true",
      "related_to_defecation": "true"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rome_iv_child_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": "Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M",
        "doi": "10.1053/j.gastro.2016.02.015",
        "id": "hyams-2016",
        "pmid": "27144632",
        "source": "Gastroenterology. 2016;150(6):1456-1468",
        "title": "Childhood Functional Gastrointestinal Disorders: Child/Adolescent"
      },
      "formula": "rome_iv_child_ibs",
      "formula_expression": "rome_iv_child_ibs iff abdominal_pain_at_least_4_days_per_month and stool_features_met >= 1 and pain_does_not_resolve_with_constipation_treatment and not_explained_by_another_condition and fulfilled_at_least_2_months; stool_features_met counts related_to_defecation, change_in_stool_frequency, and change_in_stool_form (Hyams 2016 Rome IV H2b child/adolescent IBS)",
      "criteria": [
        {
          "factor": "abdominal_pain_at_least_4_days_per_month",
          "met": true
        },
        {
          "factor": "related_to_defecation",
          "met": true
        },
        {
          "factor": "change_in_stool_frequency",
          "met": true
        },
        {
          "factor": "change_in_stool_form",
          "met": false
        },
        {
          "factor": "pain_does_not_resolve_with_constipation_treatment",
          "met": true
        },
        {
          "factor": "not_explained_by_another_condition",
          "met": true
        },
        {
          "factor": "fulfilled_at_least_2_months",
          "met": true
        },
        {
          "value": 2,
          "factor": "stool_features_ge_1",
          "met": true
        }
      ],
      "rome_iv_child_ibs": true,
      "stool_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": "Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M",
        "doi": "10.1053/j.gastro.2016.02.015",
        "id": "hyams-2016",
        "pmid": "27144632",
        "source": "Gastroenterology. 2016;150(6):1456-1468",
        "title": "Childhood Functional Gastrointestinal Disorders: Child/Adolescent"
      },
      "formula": "rome_iv_child_ibs",
      "formula_expression": "rome_iv_child_ibs iff abdominal_pain_at_least_4_days_per_month and stool_features_met >= 1 and pain_does_not_resolve_with_constipation_treatment and not_explained_by_another_condition and fulfilled_at_least_2_months; stool_features_met counts related_to_defecation, change_in_stool_frequency, and change_in_stool_form (Hyams 2016 Rome IV H2b child/adolescent IBS)",
      "criteria": [
        {
          "factor": "abdominal_pain_at_least_4_days_per_month",
          "met": true
        },
        {
          "factor": "related_to_defecation",
          "met": true
        },
        {
          "factor": "change_in_stool_frequency",
          "met": true
        },
        {
          "factor": "change_in_stool_form",
          "met": false
        },
        {
          "factor": "pain_does_not_resolve_with_constipation_treatment",
          "met": true
        },
        {
          "factor": "not_explained_by_another_condition",
          "met": true
        },
        {
          "factor": "fulfilled_at_least_2_months",
          "met": true
        },
        {
          "value": 2,
          "factor": "stool_features_ge_1",
          "met": true
        }
      ],
      "rome_iv_child_ibs": true,
      "stool_features_met": 2
    }
  ]
}
```

## Response fields

- `formula` (string): rome_iv_child_ibs
- `formula_expression` (string): Hyams 2016 Rome IV H2b: pain at least 4 days per month, at least 1 of 3 stool features, constipation-pain flag, not another condition, and 2-month duration
- `stool_features_met` (integer): Count of true stool features among related to defecation, change in stool frequency, and change in stool form (0-3)
- `rome_iv_child_ibs` (boolean): true only when pain at least 4 days per month, at least one stool feature, the constipation-pain flag, not another condition, and 2-month duration all hold. Not a diagnosis.
- `criteria` (array): Per-factor rows with factor and met; stool_features_ge_1 includes value 0-3
- `citation` (object): Hyams 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": "Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M",
    "doi": "10.1053/j.gastro.2016.02.015",
    "id": "hyams-2016",
    "pmid": "27144632",
    "source": "Gastroenterology. 2016;150(6):1456-1468",
    "title": "Childhood Functional Gastrointestinal Disorders: Child/Adolescent"
  },
  "formula": "rome_iv_child_ibs",
  "formula_expression": "rome_iv_child_ibs iff abdominal_pain_at_least_4_days_per_month and stool_features_met >= 1 and pain_does_not_resolve_with_constipation_treatment and not_explained_by_another_condition and fulfilled_at_least_2_months; stool_features_met counts related_to_defecation, change_in_stool_frequency, and change_in_stool_form (Hyams 2016 Rome IV H2b child/adolescent IBS)",
  "criteria": [
    {
      "factor": "abdominal_pain_at_least_4_days_per_month",
      "met": true
    },
    {
      "factor": "related_to_defecation",
      "met": true
    },
    {
      "factor": "change_in_stool_frequency",
      "met": true
    },
    {
      "factor": "change_in_stool_form",
      "met": false
    },
    {
      "factor": "pain_does_not_resolve_with_constipation_treatment",
      "met": true
    },
    {
      "factor": "not_explained_by_another_condition",
      "met": true
    },
    {
      "factor": "fulfilled_at_least_2_months",
      "met": true
    },
    {
      "value": 2,
      "factor": "stool_features_ge_1",
      "met": true
    }
  ],
  "rome_iv_child_ibs": true,
  "stool_features_met": 2
}
```

## Errors

- HTTP 400 `invalid_rome_iv_child_ibs`: Rome IV child IBS needs the Hyams 2016 child/adolescent H2b 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 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).
- [Rome IV Child Constipation](https://magentlab.com/docs/rome-iv-child-constipation) — Apply the Hyams 2016 Rome IV H3a functional constipation (child/adolescent) criteria and return features_met and whether the published child constipation box holds (rome_iv_child_constipation).

## 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.