Janssens gout diagnostic rule

Gout rule

Sum the Janssens 2010 diagnostic-rule points for acute gouty arthritis without joint-fluid analysis and return low (≤4), intermediate (4.5–7.5), or high (≥8).

LIVE $0.005 USDC GET /api/calc/gout_rule

Markdown: /docs/gout-rule.md · Canonical: https://magentlab.com/docs/gout-rule

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

What it computes

Sum the Janssens 2010 diagnostic-rule points for acute gouty arthritis without joint-fluid analysis and return low (≤4), intermediate (4.5–7.5), or high (≥8).

When to use

When an agent needs the published primary-care gout diagnostic-rule total and must not invent a gout diagnosis or replace synovial crystal analysis.

When not to use

Not a medical device and not a gout diagnosis. magent does not examine joints or replace synovial crystal analysis.
Serum uric acid is a caller-supplied number; magent does not assay it. mg/dL >5.88 or µmol/L >350 scores 3.5; equality does not.
Provide uric_acid_mg_dl (1–20) or uric_acid_umol_l (60–1190), not both.

Formula

gout_rule = 2*male + 2*previous_arthritis_attack + 0.5*onset_within_1_day + 1*joint_redness + 2.5*mtp1_involvement + 1.5*hypertension_or_cvd + 3.5*(uric_acid_mg_dl>5.88 | uric_acid_umol_l>350); Janssens 2010; max 13; low ≤4, intermediate 4.5-7.5, high ≥8

Citation

Title: A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis
Authors: Janssens HJEM, Fransen J, van de Lisdonk EH, van Riel PLCM, van Weel C, Janssen M
Source: Arch Intern Med. 2010;170(13):1120-1126
DOI: 10.1001/archinternmed.2010.196

Worked example

Female, no flags, uric acid 5.0 mg/dL

Given: hypertension_or_cvd=falsejoint_redness=falsemtp1_involvement=falseonset_within_1_day=falseprevious_arthritis_attack=falsesex=femaleuric_acid_mg_dl=5.0

Female and all flags false; uric_acid_mg_dl 5.0 is not >5.88 → 0
Score = 0 (max 13); gout_band = low (≤4)

All factors present

Given: hypertension_or_cvd=truejoint_redness=truemtp1_involvement=trueonset_within_1_day=trueprevious_arthritis_attack=truesex=maleuric_acid_mg_dl=6.0

male 2 + previous 2 + onset 0.5 + redness 1 + MTP1 2.5 + hypertension_or_cvd 1.5 + uric acid >5.88 3.5
Score = 13 (max 13); gout_band = high (≥8)

Also searched as

gout rule
Janssens gout
diagnostic rule acute gout
gouty arthritis score
primary care gout without synovial fluid
Janssens 2010
acute gouty arthritis
MTP1 gout score

Try

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

/api/calc/gout_rule?sex=female&previous_arthritis_attack=false&onset_within_1_day=false&joint_redness=false&mtp1_involvement=false&hypertension_or_cvd=false&uric_acid_mg_dl=5.0

Full URL: https://api.magentlab.com/api/calc/gout_rule?sex=female&previous_arthritis_attack=false&onset_within_1_day=false&joint_redness=false&mtp1_involvement=false&hypertension_or_cvd=false&uric_acid_mg_dl=5.0

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/gout_rule?sex=female&previous_arthritis_attack=false&onset_within_1_day=false&joint_redness=false&mtp1_involvement=false&hypertension_or_cvd=false&uric_acid_mg_dl=5.0"

Parameters

Name	Type	Required	Description
`sex`	string	required · female, male	Caller-assigned sex (Janssens 2010). male scores 2.0; female scores 0. magent does not assign sex.
`previous_arthritis_attack`	boolean	required	Previous patient-reported arthritis attack (Janssens 2010). true scores 2.0. magent does not take a history.
`onset_within_1_day`	boolean	required	Onset within 1 day (Janssens 2010). true scores 0.5. magent does not timestamp onset.
`joint_redness`	boolean	required	Joint redness as assigned by the caller (Janssens 2010). true scores 1.0. magent does not examine joints.
`mtp1_involvement`	boolean	required	Involvement of the first metatarsophalangeal joint (Janssens 2010). true scores 2.5. magent does not examine joints.
`hypertension_or_cvd`	boolean	required	Hypertension or one or more cardiovascular diseases (Janssens 2010). true scores 1.5. magent does not diagnose hypertension or cardiovascular disease.
`uric_acid_mg_dl`	number	optional	Serum uric acid in mg/dL (1-20). Provide this or uric_acid_umol_l, not both. Scores 3.5 when >5.88; 5.88 does not score. magent does not assay uric acid.
`uric_acid_umol_l`	number	optional	Serum uric acid in µmol/L (60-1190). Provide this or uric_acid_mg_dl, not both. Scores 3.5 when >350; 350 does not score. magent does not assay uric acid.

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/gout_rule 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": [
    {
      "hypertension_or_cvd": "false",
      "joint_redness": "false",
      "mtp1_involvement": "false",
      "onset_within_1_day": "false",
      "previous_arthritis_attack": "false",
      "sex": "female",
      "uric_acid_mg_dl": "5.0"
    },
    {
      "hypertension_or_cvd": "false",
      "joint_redness": "false",
      "mtp1_involvement": "false",
      "onset_within_1_day": "false",
      "previous_arthritis_attack": "false",
      "sex": "female",
      "uric_acid_mg_dl": "5.0"
    }
  ]
}

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/gout_rule",
  "items": [
    {
      "components": [
        {
          "factor": "male",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "previous_arthritis_attack",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "onset_within_1_day",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "joint_redness",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "mtp1_involvement",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "hypertension_or_cvd",
          "points": 0.0,
          "present": false
        },
        {
          "value": 5.0,
          "factor": "uric_acid",
          "points": 0.0,
          "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": "Janssens HJEM, Fransen J, van de Lisdonk EH, van Riel PLCM, van Weel C, Janssen M",
        "doi": "10.1001/archinternmed.2010.196",
        "id": "janssens-2010",
        "pmid": "20625017",
        "source": "Arch Intern Med. 2010;170(13):1120-1126",
        "title": "A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis"
      },
      "formula": "gout_rule",
      "formula_expression": "gout_rule = 2*male + 2*previous_arthritis_attack + 0.5*onset_within_1_day + 1*joint_redness + 2.5*mtp1_involvement + 1.5*hypertension_or_cvd + 3.5*(uric_acid_mg_dl>5.88 | uric_acid_umol_l>350); Janssens 2010; max 13; low ≤4, intermediate 4.5-7.5, high ≥8",
      "max_score": 13,
      "score": 0.0,
      "gout_band": "low"
    },
    {
      "components": [
        {
          "factor": "male",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "previous_arthritis_attack",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "onset_within_1_day",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "joint_redness",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "mtp1_involvement",
          "points": 0.0,
          "present": false
        },
        {
          "factor": "hypertension_or_cvd",
          "points": 0.0,
          "present": false
        },
        {
          "value": 5.0,
          "factor": "uric_acid",
          "points": 0.0,
          "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": "Janssens HJEM, Fransen J, van de Lisdonk EH, van Riel PLCM, van Weel C, Janssen M",
        "doi": "10.1001/archinternmed.2010.196",
        "id": "janssens-2010",
        "pmid": "20625017",
        "source": "Arch Intern Med. 2010;170(13):1120-1126",
        "title": "A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis"
      },
      "formula": "gout_rule",
      "formula_expression": "gout_rule = 2*male + 2*previous_arthritis_attack + 0.5*onset_within_1_day + 1*joint_redness + 2.5*mtp1_involvement + 1.5*hypertension_or_cvd + 3.5*(uric_acid_mg_dl>5.88 | uric_acid_umol_l>350); Janssens 2010; max 13; low ≤4, intermediate 4.5-7.5, high ≥8",
      "max_score": 13,
      "score": 0.0,
      "gout_band": "low"
    }
  ]
}

Response

Field	Type	Description
`formula`	string	gout_rule
`formula_expression`	string	Exact expression used
`score`	number	Janssens 2010 points 0-13, 0.5 steps
`max_score`	integer	Always 13
`gout_band`	string	low when score is ≤4, intermediate when 4.5-7.5, high when ≥8 (Janssens 2010). Not a gout diagnosis.
`components`	array	Per-factor points
`citation`	object	Janssens 2010 Arch Intern Med citation
`disclaimer`	string	Not-a-device notice

Example JSON

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

{
  "components": [
    {
      "factor": "male",
      "points": 0.0,
      "present": false
    },
    {
      "factor": "previous_arthritis_attack",
      "points": 0.0,
      "present": false
    },
    {
      "factor": "onset_within_1_day",
      "points": 0.0,
      "present": false
    },
    {
      "factor": "joint_redness",
      "points": 0.0,
      "present": false
    },
    {
      "factor": "mtp1_involvement",
      "points": 0.0,
      "present": false
    },
    {
      "factor": "hypertension_or_cvd",
      "points": 0.0,
      "present": false
    },
    {
      "value": 5.0,
      "factor": "uric_acid",
      "points": 0.0,
      "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": "Janssens HJEM, Fransen J, van de Lisdonk EH, van Riel PLCM, van Weel C, Janssen M",
    "doi": "10.1001/archinternmed.2010.196",
    "id": "janssens-2010",
    "pmid": "20625017",
    "source": "Arch Intern Med. 2010;170(13):1120-1126",
    "title": "A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis"
  },
  "formula": "gout_rule",
  "formula_expression": "gout_rule = 2*male + 2*previous_arthritis_attack + 0.5*onset_within_1_day + 1*joint_redness + 2.5*mtp1_involvement + 1.5*hypertension_or_cvd + 3.5*(uric_acid_mg_dl>5.88 | uric_acid_umol_l>350); Janssens 2010; max 13; low ≤4, intermediate 4.5-7.5, high ≥8",
  "max_score": 13,
  "score": 0.0,
  "gout_band": "low"
}

Client errors (HTTP 400)

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

HTTP	Code	When
400	`invalid_sex`	sex must be female or male 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_uric_acid`	uric_acid_mg_dl (1-20) or uric_acid_umol_l (60-1190) is required, not both. 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

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Alvarado score — Compute the Alvarado 1986 MANTRELS score from caller-assigned findings, temperature, WBC, and neutrophil percent.

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.
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.