# 1994 Duke criteria for infective endocarditis

Duke

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

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

## What it computes

Apply the Durack 1994 original Duke criteria for infective endocarditis and return definite, possible, or rejected from caller-assigned pathologic, major, minor, and rejected flags.

## When to use

When an agent already has caller-assigned 1994 Duke pathologic, major, minor, and rejected flags and needs the published definite / possible / rejected classification. magent does not examine the patient, read an echocardiogram, or interpret cultures.

## When not to use

- Not a medical device and not a diagnosis of infective endocarditis.
- Durack 1994 original Duke criteria only. Not Li 2000 modified Duke. Not ISCVID 2023.
- magent does not examine the patient, read an echocardiogram, or interpret cultures. The caller assigns every flag.
- Possible is the leftover 1994 category (findings consistent with IE that are neither definite nor rejected). It is not the Li 2000 1-major-plus-1-minor or 3-minor possible thresholds.

## Formula

```
definite iff pathologic_definite or clinical_definite; clinical_definite iff major_count >= 2 or (major_count >= 1 and minor_count >= 3) or minor_count >= 5; else rejected if any rejected flag; else possible (Durack 1994 original Duke). minor_suggestive_echo is not counted when major_positive_echo is true; minor_suggestive_micro is not counted when major_typical_blood_culture is true. Not Li 2000. Not ISCVID 2023
```

## Citation

[New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service](https://doi.org/10.1016/0002-9343(94)90143-0)
Durack DT, Lukes AS, Bright DK
Am J Med. 1994;96(3):200-209
DOI: [10.1016/0002-9343(94)90143-0](https://doi.org/10.1016/0002-9343(94)90143-0)

## Worked example

### Two major criteria

Given: `major_positive_echo=true, major_typical_blood_culture=true, minor_fever=false, minor_immunologic_phenomena=false, minor_predisposition=false, minor_suggestive_echo=false, minor_suggestive_micro=false, minor_vascular_phenomena=false, pathologic_definite=false, rejected_firm_alternate_diagnosis=false, rejected_no_pathology_le_4_days_antibiotics=false, rejected_resolved_le_4_days_antibiotics=false`

1. major_typical_blood_culture is true
2. major_positive_echo is true
3. major_count is 2 and minor_count is 0
4. clinical_definite holds, so classification is definite


### Major echo without double-counting suggestive echo

Given: `major_positive_echo=true, major_typical_blood_culture=false, minor_fever=false, minor_immunologic_phenomena=false, minor_predisposition=false, minor_suggestive_echo=true, minor_suggestive_micro=false, minor_vascular_phenomena=false, pathologic_definite=false, rejected_firm_alternate_diagnosis=false, rejected_no_pathology_le_4_days_antibiotics=false, rejected_resolved_le_4_days_antibiotics=false`

1. major_positive_echo is true so major_count is 1
2. minor_suggestive_echo is true but is not added to minor_count
3. minor_count is 0, so clinical_definite does not hold
4. no rejected flag is true, so classification is possible


## Also searched as

- Duke criteria
- Duke endocarditis
- Durack 1994
- infective endocarditis criteria
- Duke IE criteria
- 1994 Duke criteria
- Duke major minor criteria
- pathologic definite IE

## Parameters

- `pathologic_definite` (boolean, required): Microorganisms demonstrated by culture or histology in a vegetation, embolus, or intracardiac abscess, or pathologic lesions (vegetation or abscess) confirmed by histology showing active endocarditis (Durack 1994 pathologic definite). true or false as assigned by the caller. magent does not examine tissue.
- `major_typical_blood_culture` (boolean, required): Typical microorganism from two separate blood cultures, or persistently positive blood cultures, as assigned by the caller (Durack 1994 major typical blood culture). true or false. magent does not interpret cultures.
- `major_positive_echo` (boolean, required): Positive echocardiogram for IE: oscillating mass or vegetation, abscess, new partial dehiscence of a prosthetic valve, or new valvular regurgitation (Durack 1994 major). true or false as assigned by the caller. magent does not read an echocardiogram.
- `minor_predisposition` (boolean, required): Predisposing heart condition or intravenous drug use (Durack 1994 minor). true or false as assigned by the caller. magent does not take a history.
- `minor_fever` (boolean, required): Fever ≥38.0 C (Durack 1994 minor). true or false as assigned by the caller. magent does not measure temperature.
- `minor_vascular_phenomena` (boolean, required): Vascular phenomena (Durack 1994 minor): major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, or Janeway lesions, as assigned by the caller. magent does not examine the patient.
- `minor_immunologic_phenomena` (boolean, required): Immunologic phenomena (Durack 1994 minor): glomerulonephritis, Osler nodes, Roth spots, or rheumatoid factor, as assigned by the caller. magent does not examine the patient.
- `minor_suggestive_echo` (boolean, required): Echocardiogram consistent with IE but not meeting the major echo definition (Durack 1994 minor). true or false as assigned by the caller. Not counted in minor_count when major_positive_echo is true. magent does not read an echocardiogram.
- `minor_suggestive_micro` (boolean, required): Microbiologic evidence not meeting the major culture definition (Durack 1994 minor). true or false as assigned by the caller. Not counted in minor_count when major_typical_blood_culture is true. magent does not interpret cultures.
- `rejected_firm_alternate_diagnosis` (boolean, required): Firm alternate diagnosis explaining evidence of IE (Durack 1994 rejected). true or false as assigned by the caller. Classification is rejected only when definite does not hold.
- `rejected_resolved_le_4_days_antibiotics` (boolean, required): Manifestations of IE resolved with antibiotic therapy for 4 days or less (Durack 1994 rejected). true or false as assigned by the caller.
- `rejected_no_pathology_le_4_days_antibiotics` (boolean, required): No pathologic evidence of IE at surgery or autopsy after antibiotic therapy for 4 days or less (Durack 1994 rejected). true or false as assigned by the caller. magent does not examine tissue.

## 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/duke`
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": [
    {
      "major_positive_echo": "true",
      "major_typical_blood_culture": "true",
      "minor_fever": "false",
      "minor_immunologic_phenomena": "false",
      "minor_predisposition": "false",
      "minor_suggestive_echo": "false",
      "minor_suggestive_micro": "false",
      "minor_vascular_phenomena": "false",
      "pathologic_definite": "false",
      "rejected_firm_alternate_diagnosis": "false",
      "rejected_no_pathology_le_4_days_antibiotics": "false",
      "rejected_resolved_le_4_days_antibiotics": "false"
    },
    {
      "major_positive_echo": "true",
      "major_typical_blood_culture": "true",
      "minor_fever": "false",
      "minor_immunologic_phenomena": "false",
      "minor_predisposition": "false",
      "minor_suggestive_echo": "false",
      "minor_suggestive_micro": "false",
      "minor_vascular_phenomena": "false",
      "pathologic_definite": "false",
      "rejected_firm_alternate_diagnosis": "false",
      "rejected_no_pathology_le_4_days_antibiotics": "false",
      "rejected_resolved_le_4_days_antibiotics": "false"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/duke",
  "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": "Durack DT, Lukes AS, Bright DK",
        "doi": "10.1016/0002-9343(94)90143-0",
        "id": "durack-1994",
        "pmid": "8154507",
        "source": "Am J Med. 1994;96(3):200-209",
        "title": "New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service"
      },
      "formula": "duke",
      "formula_expression": "definite iff pathologic_definite or clinical_definite; clinical_definite iff major_count >= 2 or (major_count >= 1 and minor_count >= 3) or minor_count >= 5; else rejected if any rejected flag; else possible (Durack 1994 original Duke). minor_suggestive_echo is not counted when major_positive_echo is true; minor_suggestive_micro is not counted when major_typical_blood_culture is true. Not Li 2000. Not ISCVID 2023",
      "criteria": [
        {
          "factor": "pathologic_definite",
          "met": false
        },
        {
          "factor": "major_typical_blood_culture",
          "met": true
        },
        {
          "factor": "major_positive_echo",
          "met": true
        },
        {
          "factor": "minor_predisposition",
          "met": false
        },
        {
          "factor": "minor_fever",
          "met": false
        },
        {
          "factor": "minor_vascular_phenomena",
          "met": false
        },
        {
          "factor": "minor_immunologic_phenomena",
          "met": false
        },
        {
          "factor": "minor_suggestive_echo",
          "met": false
        },
        {
          "factor": "minor_suggestive_micro",
          "met": false
        },
        {
          "factor": "rejected_firm_alternate_diagnosis",
          "met": false
        },
        {
          "factor": "rejected_resolved_le_4_days_antibiotics",
          "met": false
        },
        {
          "factor": "rejected_no_pathology_le_4_days_antibiotics",
          "met": false
        },
        {
          "factor": "clinical_definite",
          "met": true
        },
        {
          "factor": "rejected",
          "met": false
        }
      ],
      "classification": "definite",
      "major_count": 2,
      "minor_count": 0
    },
    {
      "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": "Durack DT, Lukes AS, Bright DK",
        "doi": "10.1016/0002-9343(94)90143-0",
        "id": "durack-1994",
        "pmid": "8154507",
        "source": "Am J Med. 1994;96(3):200-209",
        "title": "New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service"
      },
      "formula": "duke",
      "formula_expression": "definite iff pathologic_definite or clinical_definite; clinical_definite iff major_count >= 2 or (major_count >= 1 and minor_count >= 3) or minor_count >= 5; else rejected if any rejected flag; else possible (Durack 1994 original Duke). minor_suggestive_echo is not counted when major_positive_echo is true; minor_suggestive_micro is not counted when major_typical_blood_culture is true. Not Li 2000. Not ISCVID 2023",
      "criteria": [
        {
          "factor": "pathologic_definite",
          "met": false
        },
        {
          "factor": "major_typical_blood_culture",
          "met": true
        },
        {
          "factor": "major_positive_echo",
          "met": true
        },
        {
          "factor": "minor_predisposition",
          "met": false
        },
        {
          "factor": "minor_fever",
          "met": false
        },
        {
          "factor": "minor_vascular_phenomena",
          "met": false
        },
        {
          "factor": "minor_immunologic_phenomena",
          "met": false
        },
        {
          "factor": "minor_suggestive_echo",
          "met": false
        },
        {
          "factor": "minor_suggestive_micro",
          "met": false
        },
        {
          "factor": "rejected_firm_alternate_diagnosis",
          "met": false
        },
        {
          "factor": "rejected_resolved_le_4_days_antibiotics",
          "met": false
        },
        {
          "factor": "rejected_no_pathology_le_4_days_antibiotics",
          "met": false
        },
        {
          "factor": "clinical_definite",
          "met": true
        },
        {
          "factor": "rejected",
          "met": false
        }
      ],
      "classification": "definite",
      "major_count": 2,
      "minor_count": 0
    }
  ]
}
```

## Response fields

- `formula` (string): duke
- `formula_expression` (string): Durack 1994 original Duke: definite if pathologic_definite or clinical_definite (2 major, or 1 major plus 3 minor, or 5 minor); else rejected if any rejected flag; else possible. Suggestive echo and suggestive micro are not double-counted with the matching major.
- `major_count` (integer): Count of true Durack 1994 major flags among major_typical_blood_culture and major_positive_echo (0-2)
- `minor_count` (integer): Count of counted Durack 1994 minor flags (0-6). minor_suggestive_echo is omitted when major_positive_echo is true; minor_suggestive_micro is omitted when major_typical_blood_culture is true
- `classification` (string): definite, possible, or rejected (Durack 1994). possible is the leftover category. Not Li 2000. Not a diagnosis.
- `criteria` (array): Per-flag rows for pathologic_definite, two majors, six minors, and three rejected flags, plus clinical_definite and rejected aggregates (factor and met)
- `citation` (object): Durack 1994 Am J Med 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": "Durack DT, Lukes AS, Bright DK",
    "doi": "10.1016/0002-9343(94)90143-0",
    "id": "durack-1994",
    "pmid": "8154507",
    "source": "Am J Med. 1994;96(3):200-209",
    "title": "New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service"
  },
  "formula": "duke",
  "formula_expression": "definite iff pathologic_definite or clinical_definite; clinical_definite iff major_count >= 2 or (major_count >= 1 and minor_count >= 3) or minor_count >= 5; else rejected if any rejected flag; else possible (Durack 1994 original Duke). minor_suggestive_echo is not counted when major_positive_echo is true; minor_suggestive_micro is not counted when major_typical_blood_culture is true. Not Li 2000. Not ISCVID 2023",
  "criteria": [
    {
      "factor": "pathologic_definite",
      "met": false
    },
    {
      "factor": "major_typical_blood_culture",
      "met": true
    },
    {
      "factor": "major_positive_echo",
      "met": true
    },
    {
      "factor": "minor_predisposition",
      "met": false
    },
    {
      "factor": "minor_fever",
      "met": false
    },
    {
      "factor": "minor_vascular_phenomena",
      "met": false
    },
    {
      "factor": "minor_immunologic_phenomena",
      "met": false
    },
    {
      "factor": "minor_suggestive_echo",
      "met": false
    },
    {
      "factor": "minor_suggestive_micro",
      "met": false
    },
    {
      "factor": "rejected_firm_alternate_diagnosis",
      "met": false
    },
    {
      "factor": "rejected_resolved_le_4_days_antibiotics",
      "met": false
    },
    {
      "factor": "rejected_no_pathology_le_4_days_antibiotics",
      "met": false
    },
    {
      "factor": "clinical_definite",
      "met": true
    },
    {
      "factor": "rejected",
      "met": false
    }
  ],
  "classification": "definite",
  "major_count": 2,
  "minor_count": 0
}
```

## 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

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- [SIRS](https://magentlab.com/docs/sirs) — Compute the Bone 1992 ACCP/SCCM SIRS criteria from temperature, heart rate, respiratory rate, and WBC, with optional PaCO2 and band percent.
- [4Ts score](https://magentlab.com/docs/four-ts) — Compute the Lo 2006 4Ts score as the sum of four caller-assigned integers 0-2 (thrombocytopenia, timing, thrombosis, other causes).

## 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.