# Mayo ulcerative colitis disease-activity index

Mayo DAI

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/mayo_uc`
HTML: https://magentlab.com/docs/mayo-uc
Markdown: https://magentlab.com/docs/mayo-uc.md

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

## What it computes

Sum four caller-assigned Schroeder 1987 ulcerative colitis disease-activity index items (each integer 0-3) and return the total (max 12). Does not return later remission or activity bands.

## When to use

When an agent has already assigned Schroeder 1987 stool frequency, rectal bleeding, endoscopy, and physician global integers and needs the four-item total, not a diagnosis, later Mayo cutoffs, PUCAI, or the Mayo SPN nodule model.

## When not to use

- Not a medical device and not a diagnosis of ulcerative colitis or a treatment order.
- Each of the four items is a caller-assigned integer 0-3 from Schroeder 1987. magent does not count stools, examine the patient, or perform endoscopy.
- Schroeder 1987 did not publish remission, mild, moderate, or severe cutoffs for the total score. magent returns score and max_score only and does not apply later Mayo or partial-Mayo bands.
- Full four-item disease-activity index including endoscopy. Not PUCAI and not the Mayo Clinic solitary-pulmonary-nodule model.

## Formula

```
Mayo DAI = stool_frequency + rectal_bleeding + endoscopy + physician_global; Schroeder 1987 caller-assigned integers 0-3 each; max 12; no published total-score activity bands
```

## Citation

[Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study](https://doi.org/10.1056/NEJM198712243172603)
Schroeder KW, Tremaine WJ, Ilstrup DM
N Engl J Med. 1987;317(26):1625-1629
DOI: [10.1056/NEJM198712243172603](https://doi.org/10.1056/NEJM198712243172603)

## Worked example

### All items 0

Given: `endoscopy=0, physician_global=0, rectal_bleeding=0, stool_frequency=0`

1. stool_frequency 0 + rectal_bleeding 0 + endoscopy 0 + physician_global 0
2. Score = 0 (max 12). No activity band.


### All items 3

Given: `endoscopy=3, physician_global=3, rectal_bleeding=3, stool_frequency=3`

1. stool_frequency 3 + rectal_bleeding 3 + endoscopy 3 + physician_global 3
2. Score = 12 (max 12). No activity band.


## Also searched as

- Mayo score
- Mayo Clinic score
- ulcerative colitis DAI
- Schroeder Mayo
- Mayo DAI
- UC disease activity index
- Mayo UC score

## Parameters

- `stool_frequency` (integer, required): Caller-assigned Schroeder 1987 stool frequency (integer 0-3): 0 normal number of stools for this patient; 1 = 1-2 stools/day more than normal; 2 = 3-4 more; 3 = 5 or more more than normal. magent does not count stools.
- `rectal_bleeding` (integer, required): Caller-assigned Schroeder 1987 rectal bleeding (integer 0-3): 0 none; 1 streaks of blood with stool less than half the time; 2 obvious blood with stool most of the time; 3 blood alone passed. magent does not examine the patient.
- `endoscopy` (integer, required): Caller-assigned Schroeder 1987 endoscopy / flexible proctosigmoidoscopy (integer 0-3): 0 normal or inactive; 1 mild (erythema, decreased vascular pattern, mild friability); 2 moderate (marked erythema, absent vascular pattern, friability, erosions); 3 severe (spontaneous bleeding, ulceration). magent does not perform endoscopy.
- `physician_global` (integer, required): Caller-assigned Schroeder 1987 physician's global assessment (integer 0-3): 0 normal; 1 mild; 2 moderate; 3 severe. 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.

Method: `POST /api/calc/mayo_uc`
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": [
    {
      "endoscopy": "0",
      "physician_global": "0",
      "rectal_bleeding": "0",
      "stool_frequency": "0"
    },
    {
      "endoscopy": "0",
      "physician_global": "0",
      "rectal_bleeding": "0",
      "stool_frequency": "0"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/mayo-uc

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/mayo_uc",
  "items": [
    {
      "components": [
        {
          "value": 0,
          "factor": "stool_frequency",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "rectal_bleeding",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "endoscopy",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "physician_global",
          "points": 0,
          "present": 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": "Schroeder KW, Tremaine WJ, Ilstrup DM",
        "doi": "10.1056/NEJM198712243172603",
        "id": "schroeder-1987",
        "pmid": "3317057",
        "source": "N Engl J Med. 1987;317(26):1625-1629",
        "title": "Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study"
      },
      "formula": "mayo_uc",
      "formula_expression": "Mayo DAI = stool_frequency + rectal_bleeding + endoscopy + physician_global; Schroeder 1987 caller-assigned integers 0-3 each; max 12; no published total-score activity bands",
      "max_score": 12,
      "score": 0,
      "endoscopy": 0,
      "physician_global": 0,
      "rectal_bleeding": 0,
      "stool_frequency": 0
    },
    {
      "components": [
        {
          "value": 0,
          "factor": "stool_frequency",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "rectal_bleeding",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "endoscopy",
          "points": 0,
          "present": true
        },
        {
          "value": 0,
          "factor": "physician_global",
          "points": 0,
          "present": 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": "Schroeder KW, Tremaine WJ, Ilstrup DM",
        "doi": "10.1056/NEJM198712243172603",
        "id": "schroeder-1987",
        "pmid": "3317057",
        "source": "N Engl J Med. 1987;317(26):1625-1629",
        "title": "Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study"
      },
      "formula": "mayo_uc",
      "formula_expression": "Mayo DAI = stool_frequency + rectal_bleeding + endoscopy + physician_global; Schroeder 1987 caller-assigned integers 0-3 each; max 12; no published total-score activity bands",
      "max_score": 12,
      "score": 0,
      "endoscopy": 0,
      "physician_global": 0,
      "rectal_bleeding": 0,
      "stool_frequency": 0
    }
  ]
}
```

## Response fields

- `formula` (string): mayo_uc
- `formula_expression` (string): Exact expression used
- `score` (integer): Schroeder 1987 disease-activity index points 0-12
- `max_score` (integer): Always 12
- `stool_frequency` (integer): Caller-assigned stool frequency 0-3
- `rectal_bleeding` (integer): Caller-assigned rectal bleeding 0-3
- `endoscopy` (integer): Caller-assigned endoscopy 0-3
- `physician_global` (integer): Caller-assigned physician global 0-3
- `components` (array): Per-item caller-assigned points
- `citation` (object): Schroeder et al. N Engl J Med 1987 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "value": 0,
      "factor": "stool_frequency",
      "points": 0,
      "present": true
    },
    {
      "value": 0,
      "factor": "rectal_bleeding",
      "points": 0,
      "present": true
    },
    {
      "value": 0,
      "factor": "endoscopy",
      "points": 0,
      "present": true
    },
    {
      "value": 0,
      "factor": "physician_global",
      "points": 0,
      "present": 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": "Schroeder KW, Tremaine WJ, Ilstrup DM",
    "doi": "10.1056/NEJM198712243172603",
    "id": "schroeder-1987",
    "pmid": "3317057",
    "source": "N Engl J Med. 1987;317(26):1625-1629",
    "title": "Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study"
  },
  "formula": "mayo_uc",
  "formula_expression": "Mayo DAI = stool_frequency + rectal_bleeding + endoscopy + physician_global; Schroeder 1987 caller-assigned integers 0-3 each; max 12; no published total-score activity bands",
  "max_score": 12,
  "score": 0,
  "endoscopy": 0,
  "physician_global": 0,
  "rectal_bleeding": 0,
  "stool_frequency": 0
}
```

## Errors

- HTTP 400 `invalid_mayo_item`: stool_frequency, rectal_bleeding, endoscopy, and physician_global must each be an integer 0-3 (Schroeder 1987). 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

- [PUCAI](https://magentlab.com/docs/pucai) — Sum six caller-assigned Turner 2007 PUCAI item points and return the published total (max 85) with activity band.
- [HBI](https://magentlab.com/docs/harvey-bradshaw) — 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.

## 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.