# Janssens gout diagnostic rule Gout rule Status: LIVE Price: $0.005 USDC `GET /api/calc/gout_rule` HTML: https://magentlab.com/docs/gout-rule Markdown: https://magentlab.com/docs/gout-rule.md 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 [A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis](https://doi.org/10.1001/archinternmed.2010.196) Janssens HJEM, Fransen J, van de Lisdonk EH, van Riel PLCM, van Weel C, Janssen M Arch Intern Med. 2010;170(13):1120-1126 DOI: [10.1001/archinternmed.2010.196](https://doi.org/10.1001/archinternmed.2010.196) ## Worked example ### Female, no flags, uric acid 5.0 mg/dL Given: `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` 1. Female and all flags false; uric_acid_mg_dl 5.0 is not >5.88 → 0 2. Score = 0 (max 13); gout_band = low (≤4) ### All factors present Given: `hypertension_or_cvd=true, joint_redness=true, mtp1_involvement=true, onset_within_1_day=true, previous_arthritis_attack=true, sex=male, uric_acid_mg_dl=6.0` 1. male 2 + previous 2 + onset 0.5 + redness 1 + MTP1 2.5 + hypertension_or_cvd 1.5 + uric acid >5.88 3.5 2. 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 ## Parameters - `sex` (string, required): 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. Method: `POST /api/calc/gout_rule` 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": [ { "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" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/gout-rule Example 200: ```json { "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 fields - `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 Frozen fixture. Not a live lookup. ```json { "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" } ``` ## Errors - HTTP 400 `invalid_sex`: sex must be female or male 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_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. - 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 - [Kocher criteria](https://magentlab.com/docs/kocher) — Sum the four Kocher 1999 predictors and return the published predicted probability of septic arthritis versus transient synovitis in children with irritable hip. - [Alvarado score](https://magentlab.com/docs/alvarado) — 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. - 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. - 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.