Emergency · LIVE

Clinical Disease Activity Index (CDAI) for RA

CDAI-RA

Sum caller-assigned 28-joint swollen and tender counts and 0–10 cm patient and evaluator globals and return the Aletaha 2005 Clinical Disease Activity Index. Does not add CRP and does not return activity-state cutoffs.

LIVE $0.005 USDC GET /api/calc/cdai_ra

Markdown: /docs/cdai-ra.md · Canonical: https://magentlab.com/docs/cdai-ra

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

What it computes

Sum caller-assigned 28-joint swollen and tender counts and 0–10 cm patient and evaluator globals and return the Aletaha 2005 Clinical Disease Activity Index. Does not add CRP and does not return activity-state cutoffs.

When to use

When an agent already has caller-assigned 28-joint swollen and tender counts and 0–10 cm patient and evaluator globals and needs the published CDAI sum (SJC+TJC+PGA+EGA), not SDAI, not Crohn's CDAI, and not later unofficial activity-state cutoffs.

When not to use

• Not a medical device and not a rheumatoid arthritis diagnosis or a treatment order.
• magent does not count joints. sjc28, tjc28, pga, and ega are caller-assigned. PGA and EGA are centimetres on a 0–10 VAS as published.
• CDAI is SJC28 + TJC28 + PGA + EGA. It does not include CRP. Not SDAI. Not Crohn's CDAI.
• Aletaha 2005 Arthritis Res Ther (ar1740) validates the sum against DAS28, SDAI, and HAQ. It does not publish activity-state cutoffs. magent returns score and max_score only.

Formula

CDAI = sjc28 + tjc28 + pga + ega; Aletaha 2005 Arthritis Res Ther (ar1740); PGA and EGA in cm on a 0-10 VAS; half points allowed; not integer-rounded; max 76; magent does not count joints; not SDAI; not Crohn's CDAI; no published activity-state cutoffs

Citation

Title

Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score

Authors

Aletaha D, Nell VPK, Stamm T, et al.

Source

Arthritis Res Ther. 2005;7(4):R796-R806

DOI

10.1186/ar1740

Worked example

Also searched as

• Clinical Disease Activity Index
• CDAI RA
• Aletaha CDAI
• rheumatoid arthritis CDAI
• CDAI without CRP
• RA clinical disease activity

Try

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

/api/calc/cdai_ra?sjc28=0&tjc28=0&pga=0&ega=0

Full URL: https://api.magentlab.com/api/calc/cdai_ra?sjc28=0&tjc28=0&pga=0&ega=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/cdai_ra?sjc28=0&tjc28=0&pga=0&ega=0"

Parameters

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/cdai_ra 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": [
    {
      "ega": "0",
      "pga": "0",
      "sjc28": "0",
      "tjc28": "0"
    },
    {
      "ega": "0",
      "pga": "0",
      "sjc28": "0",
      "tjc28": "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/cdai_ra",
  "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
        }
      ],
      "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, Nell VPK, Stamm T, et al.",
        "doi": "10.1186/ar1740",
        "id": "aletaha-2005-cdai",
        "pmid": "15987481",
        "source": "Arthritis Res Ther. 2005;7(4):R796-R806",
        "title": "Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score"
      },
      "formula": "cdai_ra",
      "formula_expression": "CDAI = sjc28 + tjc28 + pga + ega; Aletaha 2005 Arthritis Res Ther (ar1740); PGA and EGA in cm on a 0-10 VAS; half points allowed; not integer-rounded; max 76; magent does not count joints; not SDAI; not Crohn's CDAI; no published activity-state cutoffs",
      "max_score": 76,
      "score": 0.0,
      "ega": 0.0,
      "pga": 0.0,
      "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
        }
      ],
      "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, Nell VPK, Stamm T, et al.",
        "doi": "10.1186/ar1740",
        "id": "aletaha-2005-cdai",
        "pmid": "15987481",
        "source": "Arthritis Res Ther. 2005;7(4):R796-R806",
        "title": "Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score"
      },
      "formula": "cdai_ra",
      "formula_expression": "CDAI = sjc28 + tjc28 + pga + ega; Aletaha 2005 Arthritis Res Ther (ar1740); PGA and EGA in cm on a 0-10 VAS; half points allowed; not integer-rounded; max 76; magent does not count joints; not SDAI; not Crohn's CDAI; no published activity-state cutoffs",
      "max_score": 76,
      "score": 0.0,
      "ega": 0.0,
      "pga": 0.0,
      "sjc28": 0,
      "tjc28": 0
    }
  ]
}

Response

Example JSON

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

{
  "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
    }
  ],
  "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, Nell VPK, Stamm T, et al.",
    "doi": "10.1186/ar1740",
    "id": "aletaha-2005-cdai",
    "pmid": "15987481",
    "source": "Arthritis Res Ther. 2005;7(4):R796-R806",
    "title": "Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score"
  },
  "formula": "cdai_ra",
  "formula_expression": "CDAI = sjc28 + tjc28 + pga + ega; Aletaha 2005 Arthritis Res Ther (ar1740); PGA and EGA in cm on a 0-10 VAS; half points allowed; not integer-rounded; max 76; magent does not count joints; not SDAI; not Crohn's CDAI; no published activity-state cutoffs",
  "max_score": 76,
  "score": 0.0,
  "ega": 0.0,
  "pga": 0.0,
  "sjc28": 0,
  "tjc28": 0
}

Client errors (HTTP 400)

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

Related tools

• SDAI — 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.
• CASPAR — Apply the Taylor 2006 CASPAR classification criteria for psoriatic arthritis: require established inflammatory articular disease, then return the published point total (max 8) and whether score ≥3 classifies psoriatic arthritis. Not a diagnosis.
• Leiden UA rule — Sum the van der Helm-van Mil 2007 simplified Leiden prediction score for recent-onset undifferentiated arthritis and return the paper’s ≤6 / 6–8 / ≥8 decision band.

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. 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.