# Rome IV narcotic bowel syndrome

Rome IV NBS

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

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

## What it computes

Apply the Keefer 2016 Rome IV narcotic bowel syndrome (NBS / D2) diagnostic criteria and return nbs_features_met (0-3) and whether the published NBS box holds (rome_iv_nbs).

## When to use

When an agent already has the seven caller-assigned Keefer 2016 Rome IV NBS flags and needs whether the published NBS box holds. magent does not examine the patient or judge opioid dose beyond the caller flags.

## When not to use

- Not a medical device.
- Not a diagnosis. magent does not diagnose narcotic bowel syndrome.
- The caller assigns the seven flags. magent does not examine the patient or judge opioid dose beyond caller flags.
- Patients often take about 75 mg oral morphine equivalent; no particular time frame or dosage is required. That dose note is copy-only and is not parsed.
- This tool is Keefer 2016 Rome IV NBS (D2 / opioid-induced GI hyperalgesia) only. Not Rome IV CAPS (D1). Not opioid-induced constipation (rome-iv-oic).

## Formula

```
rome_iv_nbs iff chronic_or_frequently_recurring_abdominal_pain_on_narcotics and pain_not_explained_by_current_or_previous_gi_diagnosis and nbs_features_met >= 2 and fulfilled_last_3_months and onset_at_least_6_months; nbs_features_met counts pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics, marked_worsening_when_dose_wanes_improvement_when_reinstituted, and progression_of_frequency_duration_intensity_of_pain_episodes (Keefer 2016 Rome IV D2 Narcotic Bowel Syndrome / opioid-induced GI hyperalgesia)
```

## Citation

[Centrally Mediated Disorders of Gastrointestinal Pain](https://doi.org/10.1053/j.gastro.2016.02.034)
Keefer L, Drossman DA, Guthrie E, Simrén M, Tillisch K, Olden K, Whorwell PJ
Gastroenterology. 2016;150(6):1408-1419
DOI: [10.1053/j.gastro.2016.02.034](https://doi.org/10.1053/j.gastro.2016.02.034)

## Worked example

### Pain on narcotics, unexplained, 6-month onset, and two NBS features

Given: `chronic_or_frequently_recurring_abdominal_pain_on_narcotics=true, fulfilled_last_3_months=true, marked_worsening_when_dose_wanes_improvement_when_reinstituted=true, onset_at_least_6_months=true, pain_not_explained_by_current_or_previous_gi_diagnosis=true, pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics=true, progression_of_frequency_duration_intensity_of_pain_episodes=false`

1. Chronic or frequently recurring abdominal pain on narcotics is true
2. Pain is not explained by a current or previous GI diagnosis
3. Pain worsens or incompletely resolves with continued or escalating narcotics is true
4. Marked worsening when the dose wanes with improvement when re-instituted is true
5. Progression of frequency, duration, and intensity of pain episodes is false (2 of 3)
6. Criteria fulfilled for the last 3 months and onset at least 6 months prior are true
7. rome_iv_nbs is true


### Pain on narcotics with only one NBS feature

Given: `chronic_or_frequently_recurring_abdominal_pain_on_narcotics=true, fulfilled_last_3_months=true, marked_worsening_when_dose_wanes_improvement_when_reinstituted=false, onset_at_least_6_months=true, pain_not_explained_by_current_or_previous_gi_diagnosis=true, pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics=true, progression_of_frequency_duration_intensity_of_pain_episodes=false`

1. Chronic pain on narcotics, unexplained pain, last-3-months, and 6-month onset hold
2. Only worsening or incomplete resolution with continued or escalating narcotics is true (1 of 3)
3. rome_iv_nbs is false


## Also searched as

- Rome IV NBS
- Rome IV narcotic bowel syndrome
- Keefer 2016 NBS
- opioid-induced GI hyperalgesia
- narcotic bowel
- Rome IV D2 NBS
- centrally mediated narcotic bowel
- NBS diagnostic criteria
- Keefer narcotic bowel
- opioid GI hyperalgesia

## Parameters

- `chronic_or_frequently_recurring_abdominal_pain_on_narcotics` (boolean, required): Chronic or frequently recurring abdominal pain treated with acute high-dose or chronic narcotics; pain must occur most days, as assigned (Keefer 2016 Rome IV NBS / D2). Patients often take about 75 mg oral morphine equivalent; no particular time frame or dosage is required. true or false as assigned by the caller. magent does not examine the patient or judge opioid dose.
- `pain_not_explained_by_current_or_previous_gi_diagnosis` (boolean, required): The nature and intensity of the pain is not explained by a current or previous GI diagnosis (a structural diagnosis may exist but is not sufficient to explain the pain), as assigned (Keefer 2016). true or false as assigned by the caller. magent does not examine the patient.
- `pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics` (boolean, required): Pain worsens or incompletely resolves with continued or escalating dosages of narcotics (one of three NBS features; at least two required). true or false as assigned by the caller.
- `marked_worsening_when_dose_wanes_improvement_when_reinstituted` (boolean, required): Marked worsening of pain when the narcotic dose wanes and improvement when narcotics are re-instituted (soar and crash; one of three NBS features; at least two required). true or false as assigned by the caller.
- `progression_of_frequency_duration_intensity_of_pain_episodes` (boolean, required): Progression of the frequency, duration, and intensity of pain episodes (one of three NBS features; at least two required). true or false as assigned by the caller.
- `fulfilled_last_3_months` (boolean, required): Criteria fulfilled for the last 3 months, as assigned (Keefer 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 (Keefer 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_nbs`
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": [
    {
      "chronic_or_frequently_recurring_abdominal_pain_on_narcotics": "true",
      "fulfilled_last_3_months": "true",
      "marked_worsening_when_dose_wanes_improvement_when_reinstituted": "true",
      "onset_at_least_6_months": "true",
      "pain_not_explained_by_current_or_previous_gi_diagnosis": "true",
      "pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics": "true",
      "progression_of_frequency_duration_intensity_of_pain_episodes": "false"
    },
    {
      "chronic_or_frequently_recurring_abdominal_pain_on_narcotics": "true",
      "fulfilled_last_3_months": "true",
      "marked_worsening_when_dose_wanes_improvement_when_reinstituted": "true",
      "onset_at_least_6_months": "true",
      "pain_not_explained_by_current_or_previous_gi_diagnosis": "true",
      "pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics": "true",
      "progression_of_frequency_duration_intensity_of_pain_episodes": "false"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rome_iv_nbs",
  "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": "Keefer L, Drossman DA, Guthrie E, Simrén M, Tillisch K, Olden K, Whorwell PJ",
        "doi": "10.1053/j.gastro.2016.02.034",
        "id": "keefer-2016",
        "pmid": "27144628",
        "source": "Gastroenterology. 2016;150(6):1408-1419",
        "title": "Centrally Mediated Disorders of Gastrointestinal Pain"
      },
      "formula": "rome_iv_nbs",
      "formula_expression": "rome_iv_nbs iff chronic_or_frequently_recurring_abdominal_pain_on_narcotics and pain_not_explained_by_current_or_previous_gi_diagnosis and nbs_features_met >= 2 and fulfilled_last_3_months and onset_at_least_6_months; nbs_features_met counts pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics, marked_worsening_when_dose_wanes_improvement_when_reinstituted, and progression_of_frequency_duration_intensity_of_pain_episodes (Keefer 2016 Rome IV D2 Narcotic Bowel Syndrome / opioid-induced GI hyperalgesia)",
      "criteria": [
        {
          "factor": "chronic_or_frequently_recurring_abdominal_pain_on_narcotics",
          "met": true
        },
        {
          "factor": "pain_not_explained_by_current_or_previous_gi_diagnosis",
          "met": true
        },
        {
          "factor": "pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics",
          "met": true
        },
        {
          "factor": "marked_worsening_when_dose_wanes_improvement_when_reinstituted",
          "met": true
        },
        {
          "factor": "progression_of_frequency_duration_intensity_of_pain_episodes",
          "met": false
        },
        {
          "value": 2,
          "factor": "nbs_features_ge_2",
          "met": true
        },
        {
          "factor": "fulfilled_last_3_months",
          "met": true
        },
        {
          "factor": "onset_at_least_6_months",
          "met": true
        }
      ],
      "nbs_features_met": 2,
      "rome_iv_nbs": 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": "Keefer L, Drossman DA, Guthrie E, Simrén M, Tillisch K, Olden K, Whorwell PJ",
        "doi": "10.1053/j.gastro.2016.02.034",
        "id": "keefer-2016",
        "pmid": "27144628",
        "source": "Gastroenterology. 2016;150(6):1408-1419",
        "title": "Centrally Mediated Disorders of Gastrointestinal Pain"
      },
      "formula": "rome_iv_nbs",
      "formula_expression": "rome_iv_nbs iff chronic_or_frequently_recurring_abdominal_pain_on_narcotics and pain_not_explained_by_current_or_previous_gi_diagnosis and nbs_features_met >= 2 and fulfilled_last_3_months and onset_at_least_6_months; nbs_features_met counts pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics, marked_worsening_when_dose_wanes_improvement_when_reinstituted, and progression_of_frequency_duration_intensity_of_pain_episodes (Keefer 2016 Rome IV D2 Narcotic Bowel Syndrome / opioid-induced GI hyperalgesia)",
      "criteria": [
        {
          "factor": "chronic_or_frequently_recurring_abdominal_pain_on_narcotics",
          "met": true
        },
        {
          "factor": "pain_not_explained_by_current_or_previous_gi_diagnosis",
          "met": true
        },
        {
          "factor": "pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics",
          "met": true
        },
        {
          "factor": "marked_worsening_when_dose_wanes_improvement_when_reinstituted",
          "met": true
        },
        {
          "factor": "progression_of_frequency_duration_intensity_of_pain_episodes",
          "met": false
        },
        {
          "value": 2,
          "factor": "nbs_features_ge_2",
          "met": true
        },
        {
          "factor": "fulfilled_last_3_months",
          "met": true
        },
        {
          "factor": "onset_at_least_6_months",
          "met": true
        }
      ],
      "nbs_features_met": 2,
      "rome_iv_nbs": true
    }
  ]
}
```

## Response fields

- `formula` (string): rome_iv_nbs
- `formula_expression` (string): Keefer 2016 Rome IV NBS / D2: chronic or frequently recurring abdominal pain on narcotics, pain not explained by a current or previous GI diagnosis, at least 2 of 3 NBS features, last-3-months criteria, and 6-month onset
- `nbs_features_met` (integer): Count of true NBS features among worsening or incomplete resolution with continued or escalating narcotics, marked worsening when the dose wanes with improvement when re-instituted, and progression of frequency, duration, and intensity of pain episodes (0-3)
- `rome_iv_nbs` (boolean): true only when chronic pain on narcotics, pain not explained by a GI diagnosis, at least two NBS features, last-3-months criteria, and 6-month onset all hold. Not a diagnosis.
- `criteria` (array): Per-factor rows with factor and met; nbs_features_ge_2 includes value 0-3
- `citation` (object): Keefer 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": "Keefer L, Drossman DA, Guthrie E, Simrén M, Tillisch K, Olden K, Whorwell PJ",
    "doi": "10.1053/j.gastro.2016.02.034",
    "id": "keefer-2016",
    "pmid": "27144628",
    "source": "Gastroenterology. 2016;150(6):1408-1419",
    "title": "Centrally Mediated Disorders of Gastrointestinal Pain"
  },
  "formula": "rome_iv_nbs",
  "formula_expression": "rome_iv_nbs iff chronic_or_frequently_recurring_abdominal_pain_on_narcotics and pain_not_explained_by_current_or_previous_gi_diagnosis and nbs_features_met >= 2 and fulfilled_last_3_months and onset_at_least_6_months; nbs_features_met counts pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics, marked_worsening_when_dose_wanes_improvement_when_reinstituted, and progression_of_frequency_duration_intensity_of_pain_episodes (Keefer 2016 Rome IV D2 Narcotic Bowel Syndrome / opioid-induced GI hyperalgesia)",
  "criteria": [
    {
      "factor": "chronic_or_frequently_recurring_abdominal_pain_on_narcotics",
      "met": true
    },
    {
      "factor": "pain_not_explained_by_current_or_previous_gi_diagnosis",
      "met": true
    },
    {
      "factor": "pain_worsens_or_incompletely_resolves_with_continued_or_escalating_narcotics",
      "met": true
    },
    {
      "factor": "marked_worsening_when_dose_wanes_improvement_when_reinstituted",
      "met": true
    },
    {
      "factor": "progression_of_frequency_duration_intensity_of_pain_episodes",
      "met": false
    },
    {
      "value": 2,
      "factor": "nbs_features_ge_2",
      "met": true
    },
    {
      "factor": "fulfilled_last_3_months",
      "met": true
    },
    {
      "factor": "onset_at_least_6_months",
      "met": true
    }
  ],
  "nbs_features_met": 2,
  "rome_iv_nbs": true
}
```

## Errors

- HTTP 400 `invalid_rome_iv_nbs`: Rome IV narcotic bowel needs the Keefer 2016 centrally mediated NBS 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 CAPS](https://magentlab.com/docs/rome-iv-caps) — Apply the Keefer 2016 Rome IV centrally mediated abdominal pain syndrome (CAPS / D1) diagnostic criteria and return whether the published CAPS box holds (rome_iv_caps).
- [Rome IV OIC](https://magentlab.com/docs/rome-iv-oic) — Apply the Mearin 2016 Rome IV C6 opioid-induced constipation criteria and return symptom_count (0-6) and whether the published C6 box holds (rome_iv_oic).

## 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.