# Simplified Disease Activity Index (SDAI) SDAI Status: LIVE Price: $0.005 USDC `GET /api/calc/sdai` HTML: https://magentlab.com/docs/sdai Markdown: https://magentlab.com/docs/sdai.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Sum caller-assigned 28-joint swollen and tender counts, 0–10 cm patient and evaluator globals, and CRP in mg/dL, and return the Aletaha 2005 SDAI with the newly proposed activity state. ## When to use When an agent already has 28-joint swollen and tender counts, 0–10 cm patient and evaluator globals, and CRP in mg/dL and needs the published SDAI sum and Aletaha 2005 newly proposed activity state, not the original 5/20/40 cutoffs. ## When not to use - Not a medical device and not a rheumatoid arthritis diagnosis or a treatment order. - magent does not count joints or assay CRP. sjc28, tjc28, pga, ega, and crp_mg_dl are caller-assigned. CRP is mg/dL as published, not mg/L. The 0–30 CRP range is a magent clamp. - Uses the Aletaha 2005 newly proposed SDAI definition (≤3.3 remission, ≤11 low, ≤26 moderate, >26 high), not the original 5/20/40 cutoffs. - Not CDAI (SDAI without CRP). Not Crohn's CDAI. Not DAS28. ## Formula ``` SDAI = sjc28 + tjc28 + pga + ega + crp_mg_dl; Aletaha 2005 newly proposed definition; ≤3.3 remission, >3.3 and ≤11 low, >11 and ≤26 moderate, >26 high; half points allowed; not original 5/20/40; magent does not count joints or assay CRP ``` ## Citation [Remission and active disease in rheumatoid arthritis: defining criteria for disease activity states](https://doi.org/10.1002/art.21235) Aletaha D, Ward MM, Machold KP, Nell VPK, Stamm T, Smolen JS Arthritis Rheum. 2005;52(9):2625-2636 DOI: [10.1002/art.21235](https://doi.org/10.1002/art.21235) ## Worked example ### CRP 0.4 mg/dL, clinical zeros Given: `crp_mg_dl=0.4, ega=0, pga=0, sjc28=0, tjc28=0` 1. sjc28 0 + tjc28 0 + pga 0 + ega 0 + crp_mg_dl 0.4 2. score = 0.4 (≤3.3), sdai_band remission ### Score 3.3 is remission Given: `crp_mg_dl=0, ega=0, pga=3.3, sjc28=0, tjc28=0` 1. pga 3.3; remaining terms 0 2. score = 3.3 (≤3.3), sdai_band remission ## Also searched as - Simplified Disease Activity Index - SDAI - Aletaha SDAI - rheumatoid arthritis SDAI - SDAI disease activity - RA simplified disease activity ## Parameters - `sjc28` (integer, required): Caller-assigned swollen joint count on the 28-joint set (Aletaha 2005). Integer 0-28. magent does not count joints. - `tjc28` (integer, required): Caller-assigned tender joint count on the 28-joint set (Aletaha 2005). Integer 0-28. magent does not count joints. - `pga` (number, required): Caller-assigned patient global assessment on a 0-10 cm VAS (Aletaha 2005). Number 0-10. magent does not examine the patient. - `ega` (number, required): Caller-assigned evaluator global assessment on a 0-10 cm VAS (Aletaha 2005). Number 0-10. magent does not examine the patient. - `crp_mg_dl` (number, required): Caller-assigned C-reactive protein in mg/dL (Aletaha 2005; not mg/L). Number 0-30 is a magent clamp. magent does not assay CRP. ## 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/sdai` 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": [ { "crp_mg_dl": "0.4", "ega": "0", "pga": "0", "sjc28": "0", "tjc28": "0" }, { "crp_mg_dl": "0.4", "ega": "0", "pga": "0", "sjc28": "0", "tjc28": "0" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/sdai Example 200: ```json { "count": 2, "path": "/api/calc/sdai", "items": [ { "components": [ { "value": 0, "factor": "sjc28", "points": 0, "present": true }, { "value": 0, "factor": "tjc28", "points": 0, "present": true }, { "value": 0.0, "factor": "pga", "points": 0.0, "present": true }, { "value": 0.0, "factor": "ega", "points": 0.0, "present": true }, { "value": 0.4, "factor": "crp_mg_dl", "points": 0.4, "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": "Aletaha D, Ward MM, Machold KP, Nell VPK, Stamm T, Smolen JS", "doi": "10.1002/art.21235", "id": "aletaha-2005", "pmid": "16142705", "source": "Arthritis Rheum. 2005;52(9):2625-2636", "title": "Remission and active disease in rheumatoid arthritis: defining criteria for disease activity states" }, "formula": "sdai", "formula_expression": "SDAI = sjc28 + tjc28 + pga + ega + crp_mg_dl; Aletaha 2005 newly proposed definition; ≤3.3 remission, >3.3 and ≤11 low, >11 and ≤26 moderate, >26 high; half points allowed; not original 5/20/40; magent does not count joints or assay CRP", "max_score": 106, "score": 0.4, "crp_mg_dl": 0.4, "ega": 0.0, "pga": 0.0, "sdai_band": "remission", "sjc28": 0, "tjc28": 0 }, { "components": [ { "value": 0, "factor": "sjc28", "points": 0, "present": true }, { "value": 0, "factor": "tjc28", "points": 0, "present": true }, { "value": 0.0, "factor": "pga", "points": 0.0, "present": true }, { "value": 0.0, "factor": "ega", "points": 0.0, "present": true }, { "value": 0.4, "factor": "crp_mg_dl", "points": 0.4, "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": "Aletaha D, Ward MM, Machold KP, Nell VPK, Stamm T, Smolen JS", "doi": "10.1002/art.21235", "id": "aletaha-2005", "pmid": "16142705", "source": "Arthritis Rheum. 2005;52(9):2625-2636", "title": "Remission and active disease in rheumatoid arthritis: defining criteria for disease activity states" }, "formula": "sdai", "formula_expression": "SDAI = sjc28 + tjc28 + pga + ega + crp_mg_dl; Aletaha 2005 newly proposed definition; ≤3.3 remission, >3.3 and ≤11 low, >11 and ≤26 moderate, >26 high; half points allowed; not original 5/20/40; magent does not count joints or assay CRP", "max_score": 106, "score": 0.4, "crp_mg_dl": 0.4, "ega": 0.0, "pga": 0.0, "sdai_band": "remission", "sjc28": 0, "tjc28": 0 } ] } ``` ## Response fields - `formula` (string): sdai - `formula_expression` (string): Exact expression used - `score` (number): SDAI sum sjc28 + tjc28 + pga + ega + crp_mg_dl. Not integer-rounded; half points allowed. Theoretical max 106. - `max_score` (integer): Always 106 (28+28+10+10+30 magent CRP clamp) - `sdai_band` (string): Aletaha 2005 newly proposed SDAI state: remission (≤3.3), low (>3.3 and ≤11), moderate (>11 and ≤26), or high (>26). Not original 5/20/40. - `sjc28` (integer): Swollen 28-joint count used - `tjc28` (integer): Tender 28-joint count used - `pga` (number): Patient global 0-10 cm VAS used - `ega` (number): Evaluator global 0-10 cm VAS used - `crp_mg_dl` (number): CRP in mg/dL used - `components` (array): Per-variable points - `citation` (object): Aletaha et al. Arthritis Rheum 2005 citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "components": [ { "value": 0, "factor": "sjc28", "points": 0, "present": true }, { "value": 0, "factor": "tjc28", "points": 0, "present": true }, { "value": 0.0, "factor": "pga", "points": 0.0, "present": true }, { "value": 0.0, "factor": "ega", "points": 0.0, "present": true }, { "value": 0.4, "factor": "crp_mg_dl", "points": 0.4, "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": "Aletaha D, Ward MM, Machold KP, Nell VPK, Stamm T, Smolen JS", "doi": "10.1002/art.21235", "id": "aletaha-2005", "pmid": "16142705", "source": "Arthritis Rheum. 2005;52(9):2625-2636", "title": "Remission and active disease in rheumatoid arthritis: defining criteria for disease activity states" }, "formula": "sdai", "formula_expression": "SDAI = sjc28 + tjc28 + pga + ega + crp_mg_dl; Aletaha 2005 newly proposed definition; ≤3.3 remission, >3.3 and ≤11 low, >11 and ≤26 moderate, >26 high; half points allowed; not original 5/20/40; magent does not count joints or assay CRP", "max_score": 106, "score": 0.4, "crp_mg_dl": 0.4, "ega": 0.0, "pga": 0.0, "sdai_band": "remission", "sjc28": 0, "tjc28": 0 } ``` ## Errors - HTTP 400 `invalid_sdai`: sjc28 and tjc28 must be integers 0–28; pga and ega numbers 0–10; crp_mg_dl a number 0–30 (Aletaha 2005 SDAI disease-activity states). 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 - [ACR/EULAR gout](https://magentlab.com/docs/acr-eular-gout) — Apply the 2015 ACR/EULAR gout classification criteria (Neogi Table 2): require the entry episode, classify immediately if MSU crystals are present, otherwise return the Step 3 score (max 23) and whether score ≥8 classifies gout. Not a gout diagnosis. - [ACR/EULAR PMR](https://magentlab.com/docs/acr-eular-pmr) — Apply the 2012 EULAR/ACR polymyalgia rheumatica classification criteria (Dasgupta Table 4): require age ≥50, bilateral shoulder aching, and abnormal CRP and/or ESR, then return the clinical score with or without optional ultrasound and whether the published cut point classifies PMR. Not a PMR diagnosis. - [ACR/EULAR Sjögren](https://magentlab.com/docs/acr-eular-sjogren) — Apply the 2016 ACR/EULAR classification criteria for primary Sjögren's syndrome (Shiboski Table 3): require published inclusion and no exclusion, then return the five-item weighted score and whether the ≥4 cut point classifies primary Sjögren's syndrome. Not a diagnosis. ## 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.