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Harvey–Bradshaw simple Crohn's activity index (HBI)

HBI

Sum Harvey 1980 simple-index items (previous-day well-being, abdominal pain, liquid stools, abdominal mass, and one point per listed complication) and return the total. Does not return later remission or activity bands.

LIVE $0.005 USDC GET /api/calc/harvey_bradshaw

Markdown: /docs/harvey-bradshaw.md · Canonical: https://magentlab.com/docs/harvey-bradshaw

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

What it computes

Sum Harvey 1980 simple-index items (previous-day well-being, abdominal pain, liquid stools, abdominal mass, and one point per listed complication) and return the total. Does not return later remission or activity bands.

When to use

When an agent has already assigned the 1980 letter item integers and complication flags for the previous day and needs the simple index total, not a Crohn's diagnosis, Best 1976 CDAI, or later HBI remission cutoffs.

When not to use

  • Not a medical device and not a Crohn's diagnosis or a treatment order.
  • magent does not examine the patient. Each item and complication flag is caller-assigned.
  • Items 1–3 (well-being, abdominal pain, liquid stools) are the previous day as in the 1980 letter. This is a one-day simple index, not the Best 1976 CDAI.
  • The 1980 letter does not define remission or activity bands. magent returns score and max_score only and does not apply later HBI remission cutoffs.

Formula

HBI = well_being + abdominal_pain + liquid_stools + abdominal_mass + 1 per listed complication; Harvey 1980 previous-day items; magent max 48 (liquid_stools clamp 0-30)

Citation

Title
A simple index of Crohn's-disease activity
Authors
Harvey RF, Bradshaw JM
Source
Lancet. 1980;1(8167):514
DOI
10.1016/s0140-6736(80)92767-1

Worked example

All items 0, all flags false

Given: abdominal_mass=0abdominal_pain=0abscess=falseanal_fissure=falseaphthous_ulcers=falsearthralgia=falseerythema_nodosum=falseliquid_stools=0new_fistula=falsepyoderma_gangrenosum=falseuveitis=falsewell_being=0

  1. well_being 0 + abdominal_pain 0 + liquid_stools 0 + abdominal_mass 0 + 0 complications
  2. Score = 0 (max 48). No activity band.

Magent clamp maximum

Given: abdominal_mass=3abdominal_pain=3abscess=trueanal_fissure=trueaphthous_ulcers=truearthralgia=trueerythema_nodosum=trueliquid_stools=30new_fistula=truepyoderma_gangrenosum=trueuveitis=truewell_being=4

  1. well_being 4 + abdominal_pain 3 + liquid_stools 30 + abdominal_mass 3 + 8 complications
  2. Score = 48 (max 48). Liquid stools 30 is a magent clamp, not a published maximum.

Also searched as

  • Harvey-Bradshaw Index
  • HBI
  • simple Crohn's activity index
  • Harvey Bradshaw 1980
  • Crohn's disease activity HBI
  • HBI score
  • simple CDAI

Try

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

/api/calc/harvey_bradshaw?well_being=0&abdominal_pain=0&liquid_stools=0&abdominal_mass=0&arthralgia=false&uveitis=false&erythema_nodosum=false&aphthous_ulcers=false&pyoderma_gangrenosum=false&anal_fissure=false&new_fistula=false&abscess=false

Full URL: https://api.magentlab.com/api/calc/harvey_bradshaw?well_being=0&abdominal_pain=0&liquid_stools=0&abdominal_mass=0&arthralgia=false&uveitis=false&erythema_nodosum=false&aphthous_ulcers=false&pyoderma_gangrenosum=false&anal_fissure=false&new_fistula=false&abscess=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/harvey_bradshaw?well_being=0&abdominal_pain=0&liquid_stools=0&abdominal_mass=0&arthralgia=false&uveitis=false&erythema_nodosum=false&aphthous_ulcers=false&pyoderma_gangrenosum=false&anal_fissure=false&new_fistula=false&abscess=false"

Parameters

Name Type Required Description
well_being integer required Caller-assigned Harvey 1980 general well-being for the previous day (integer 0-4): 0 very well; 1 slightly below par; 2 poor; 3 very poor; 4 terrible. magent does not examine the patient.
abdominal_pain integer required Caller-assigned Harvey 1980 abdominal pain for the previous day (integer 0-3): 0 none; 1 mild; 2 moderate; 3 severe. magent does not examine the patient.
liquid_stools integer required Count of liquid stools that day (Harvey 1980; 1 point per stool). Integer 0-30 is a magent clamp, not a published maximum. magent does not examine the patient.
abdominal_mass integer required Caller-assigned Harvey 1980 abdominal mass (integer 0-3): 0 none; 1 dubious; 2 definite; 3 definite and tender. magent does not examine the patient.
arthralgia boolean required Arthralgia present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
uveitis boolean required Uveitis present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
erythema_nodosum boolean required Erythema nodosum present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
aphthous_ulcers boolean required Aphthous ulcers present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
pyoderma_gangrenosum boolean required Pyoderma gangrenosum present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
anal_fissure boolean required Anal fissure present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
new_fistula boolean required New fistula present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.
abscess boolean required Abscess present (Harvey 1980 complications as used for the simple index). true or false. 1 point if true. magent does not examine the patient.

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/harvey_bradshaw 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": [
    {
      "abdominal_mass": "0",
      "abdominal_pain": "0",
      "abscess": "false",
      "anal_fissure": "false",
      "aphthous_ulcers": "false",
      "arthralgia": "false",
      "erythema_nodosum": "false",
      "liquid_stools": "0",
      "new_fistula": "false",
      "pyoderma_gangrenosum": "false",
      "uveitis": "false",
      "well_being": "0"
    },
    {
      "abdominal_mass": "0",
      "abdominal_pain": "0",
      "abscess": "false",
      "anal_fissure": "false",
      "aphthous_ulcers": "false",
      "arthralgia": "false",
      "erythema_nodosum": "false",
      "liquid_stools": "0",
      "new_fistula": "false",
      "pyoderma_gangrenosum": "false",
      "uveitis": "false",
      "well_being": "0"
    }
  ]
}

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/harvey_bradshaw",
  "items": [
    {
      "components": [
        {
          "value": 0,
          "factor": "well_being",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "abdominal_pain",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "liquid_stools",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "abdominal_mass",
          "points": 0,
          "present": true
        },
        {
          "factor": "arthralgia",
          "points": 0,
          "present": false
        },
        {
          "factor": "uveitis",
          "points": 0,
          "present": false
        },
        {
          "factor": "erythema_nodosum",
          "points": 0,
          "present": false
        },
        {
          "factor": "aphthous_ulcers",
          "points": 0,
          "present": false
        },
        {
          "factor": "pyoderma_gangrenosum",
          "points": 0,
          "present": false
        },
        {
          "factor": "anal_fissure",
          "points": 0,
          "present": false
        },
        {
          "factor": "new_fistula",
          "points": 0,
          "present": false
        },
        {
          "factor": "abscess",
          "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": "Harvey RF, Bradshaw JM",
        "doi": "10.1016/s0140-6736(80)92767-1",
        "id": "harvey-bradshaw-1980",
        "pmid": "6102236",
        "source": "Lancet. 1980;1(8167):514",
        "title": "A simple index of Crohn's-disease activity"
      },
      "formula": "harvey_bradshaw",
      "formula_expression": "HBI = well_being + abdominal_pain + liquid_stools + abdominal_mass + 1 per listed complication; Harvey 1980 previous-day items; magent max 48 (liquid_stools clamp 0-30)",
      "max_score": 48,
      "score": 0,
      "abdominal_mass": 0,
      "abdominal_pain": 0,
      "abscess": false,
      "anal_fissure": false,
      "aphthous_ulcers": false,
      "arthralgia": false,
      "erythema_nodosum": false,
      "liquid_stools": 0,
      "new_fistula": false,
      "pyoderma_gangrenosum": false,
      "uveitis": false,
      "well_being": 0
    },
    {
      "components": [
        {
          "value": 0,
          "factor": "well_being",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "abdominal_pain",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "liquid_stools",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "abdominal_mass",
          "points": 0,
          "present": true
        },
        {
          "factor": "arthralgia",
          "points": 0,
          "present": false
        },
        {
          "factor": "uveitis",
          "points": 0,
          "present": false
        },
        {
          "factor": "erythema_nodosum",
          "points": 0,
          "present": false
        },
        {
          "factor": "aphthous_ulcers",
          "points": 0,
          "present": false
        },
        {
          "factor": "pyoderma_gangrenosum",
          "points": 0,
          "present": false
        },
        {
          "factor": "anal_fissure",
          "points": 0,
          "present": false
        },
        {
          "factor": "new_fistula",
          "points": 0,
          "present": false
        },
        {
          "factor": "abscess",
          "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": "Harvey RF, Bradshaw JM",
        "doi": "10.1016/s0140-6736(80)92767-1",
        "id": "harvey-bradshaw-1980",
        "pmid": "6102236",
        "source": "Lancet. 1980;1(8167):514",
        "title": "A simple index of Crohn's-disease activity"
      },
      "formula": "harvey_bradshaw",
      "formula_expression": "HBI = well_being + abdominal_pain + liquid_stools + abdominal_mass + 1 per listed complication; Harvey 1980 previous-day items; magent max 48 (liquid_stools clamp 0-30)",
      "max_score": 48,
      "score": 0,
      "abdominal_mass": 0,
      "abdominal_pain": 0,
      "abscess": false,
      "anal_fissure": false,
      "aphthous_ulcers": false,
      "arthralgia": false,
      "erythema_nodosum": false,
      "liquid_stools": 0,
      "new_fistula": false,
      "pyoderma_gangrenosum": false,
      "uveitis": false,
      "well_being": 0
    }
  ]
}

Response

Field Type Description
formula string harvey_bradshaw
formula_expression string Exact expression used
score integer Harvey 1980 simple-index points; magent clamp 0-48
max_score integer Always 48 (4+3+30+3+8 magent clamp). Not a published stool maximum.
well_being integer Caller-assigned well-being 0-4
abdominal_pain integer Caller-assigned abdominal pain 0-3
liquid_stools integer Liquid stool count that day (magent clamp 0-30)
abdominal_mass integer Caller-assigned abdominal mass 0-3
arthralgia boolean Arthralgia flag; 1 point if true
uveitis boolean Uveitis flag; 1 point if true
erythema_nodosum boolean Erythema nodosum flag; 1 point if true
aphthous_ulcers boolean Aphthous ulcers flag; 1 point if true
pyoderma_gangrenosum boolean Pyoderma gangrenosum flag; 1 point if true
anal_fissure boolean Anal fissure flag; 1 point if true
new_fistula boolean New fistula flag; 1 point if true
abscess boolean Abscess flag; 1 point if true
components array Per-item points
citation object Harvey and Bradshaw Lancet 1980 citation
disclaimer string Not-a-device notice

Example JSON

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

{
  "components": [
    {
      "value": 0,
      "factor": "well_being",
      "points": 0,
      "present": true
    },
    {
      "value": 0,
      "factor": "abdominal_pain",
      "points": 0,
      "present": true
    },
    {
      "value": 0,
      "factor": "liquid_stools",
      "points": 0,
      "present": true
    },
    {
      "value": 0,
      "factor": "abdominal_mass",
      "points": 0,
      "present": true
    },
    {
      "factor": "arthralgia",
      "points": 0,
      "present": false
    },
    {
      "factor": "uveitis",
      "points": 0,
      "present": false
    },
    {
      "factor": "erythema_nodosum",
      "points": 0,
      "present": false
    },
    {
      "factor": "aphthous_ulcers",
      "points": 0,
      "present": false
    },
    {
      "factor": "pyoderma_gangrenosum",
      "points": 0,
      "present": false
    },
    {
      "factor": "anal_fissure",
      "points": 0,
      "present": false
    },
    {
      "factor": "new_fistula",
      "points": 0,
      "present": false
    },
    {
      "factor": "abscess",
      "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": "Harvey RF, Bradshaw JM",
    "doi": "10.1016/s0140-6736(80)92767-1",
    "id": "harvey-bradshaw-1980",
    "pmid": "6102236",
    "source": "Lancet. 1980;1(8167):514",
    "title": "A simple index of Crohn's-disease activity"
  },
  "formula": "harvey_bradshaw",
  "formula_expression": "HBI = well_being + abdominal_pain + liquid_stools + abdominal_mass + 1 per listed complication; Harvey 1980 previous-day items; magent max 48 (liquid_stools clamp 0-30)",
  "max_score": 48,
  "score": 0,
  "abdominal_mass": 0,
  "abdominal_pain": 0,
  "abscess": false,
  "anal_fissure": false,
  "aphthous_ulcers": false,
  "arthralgia": false,
  "erythema_nodosum": false,
  "liquid_stools": 0,
  "new_fistula": false,
  "pyoderma_gangrenosum": false,
  "uveitis": false,
  "well_being": 0
}

Client errors (HTTP 400)

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

HTTP Code When
400 invalid_hbi well_being 0-4, abdominal_pain 0-3, and abdominal_mass 0-3 (Harvey 1980). Returned before settlement; you are not charged.
400 invalid_liquid_stools liquid_stools must be an integer from 0 to 30 (Harvey 1980 count; magent clamp). 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

  • PUCAI — Sum six caller-assigned Turner 2007 PUCAI item points and return the published total (max 85) with activity band.

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. 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.