MAGENT

Emergency · LIVE

DAS28-CRP (28-joint Disease Activity Score)

DAS28-CRP

Compute the Wells 2009 28-joint Disease Activity Score based on C-reactive protein from caller-assigned TJC28, SJC28, CRP in mg/L, and 0–100 mm general health, including the +0.96 constant, and return DAS28-defined remission when the score is <2.6.

LIVE $0.005 USDC GET /api/calc/das28_crp

Markdown: /docs/das28-crp.md · Canonical: https://magentlab.com/docs/das28-crp

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

What it computes

Compute the Wells 2009 28-joint Disease Activity Score based on C-reactive protein from caller-assigned TJC28, SJC28, CRP in mg/L, and 0–100 mm general health, including the +0.96 constant, and return DAS28-defined remission when the score is <2.6.

When to use

When an agent already has caller-assigned 28-joint tender and swollen counts, CRP in mg/L, and general health on a 0–100 mm VAS and needs the published Wells 2009 DAS28(CRP), not DAS28-ESR, not SDAI (CRP mg/dL and 0–10 globals), and not CDAI.

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. tjc28, sjc28, crp_mg_l, and gh are caller-assigned. CRP is mg/L as published, not mg/dL (SDAI). GH is 0–100 mm VAS, not 0–10 cm. The 0–500 CRP range is a magent clamp.
  • Computes DAS28(CRP) only, including the +0.96 constant. Does not compute DAS28(ESR). Not SDAI. Not CDAI.
  • Wells 2009 classifies DAS28-defined remission as a score <2.6. EULAR good/moderate/none response in that paper needs a prior DAS28 and is not this tool. magent does not apply 3.2/5.1 as single-visit activity bands.

Formula

DAS28(CRP) = 0.56*sqrt(tjc28) + 0.28*sqrt(sjc28) + 0.014*gh + 0.36*ln(crp_mg_l+1) + 0.96; Wells 2009; CRP mg/L; GH 0-100 mm VAS; remission DAS28<2.6; not DAS28-ESR; not SDAI; not CDAI; magent does not count joints or assay CRP

Citation

Title
Validation of the 28-joint Disease Activity Score (DAS28) and European League Against Rheumatism response criteria based on C-reactive protein against disease progression in patients with rheumatoid arthritis, and comparison with the DAS28 based on erythrocyte sedimentation rate
Authors
Wells G, Becker JC, Teng J, Dougados M, Schiff M, Smolen J, Aletaha D, van Riel PLCM
Source
Ann Rheum Dis. 2009;68(6):954-960
DOI
10.1136/ard.2007.084459

Worked example

TJC 0, SJC 0, CRP 1 mg/L, GH 0

Given: crp_mg_l=1gh=0sjc28=0tjc28=0

  1. sqrt(tjc28) and sqrt(sjc28) are 0; 0.014*gh is 0
  2. 0.36*ln(1+1) + 0.96 = 0.36*ln(2)+0.96
  3. score 1.21 (<2.6), das28_crp_band remission

Clinical zeros isolate the +0.96 constant

Given: crp_mg_l=0gh=0sjc28=0tjc28=0

  1. ln(0+1) = 0; joint square roots 0; GH term 0
  2. score = 0.96 (<2.6), das28_crp_band remission

Also searched as

  • DAS28 CRP
  • DAS28-CRP
  • 28-joint disease activity score CRP
  • Wells DAS28 CRP
  • DAS28 C-reactive protein
  • RA DAS28 CRP
  • DAS28 CRP remission

Try

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

/api/calc/das28_crp?tjc28=0&sjc28=0&crp_mg_l=1&gh=0

Full URL: https://api.magentlab.com/api/calc/das28_crp?tjc28=0&sjc28=0&crp_mg_l=1&gh=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/das28_crp?tjc28=0&sjc28=0&crp_mg_l=1&gh=0"

Parameters

Name Type Required Description
tjc28 integer required Caller-assigned tender joint count on the 28-joint set (Wells 2009 DAS28-CRP). Integer 0-28. magent does not count joints.
sjc28 integer required Caller-assigned swollen joint count on the 28-joint set (Wells 2009 DAS28-CRP). Integer 0-28. magent does not count joints.
crp_mg_l number required Caller-assigned C-reactive protein in mg/L (Wells 2009; not mg/dL SDAI). Number 0-500 is a magent clamp. magent does not assay CRP.
gh number required Caller-assigned general health (patient assessment) on a 0-100 mm VAS (Wells 2009; 0=best, 100=worst). Number 0-100. Not 0-10 cm SDAI PGA. magent does not examine the patient.

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/das28_crp 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": [
    {
      "crp_mg_l": "1",
      "gh": "0",
      "sjc28": "0",
      "tjc28": "0"
    },
    {
      "crp_mg_l": "1",
      "gh": "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/das28_crp",
  "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": "Wells G, Becker JC, Teng J, Dougados M, Schiff M, Smolen J, Aletaha D, van Riel PLCM",
        "doi": "10.1136/ard.2007.084459",
        "id": "wells-2009",
        "pmid": "18490431",
        "source": "Ann Rheum Dis. 2009;68(6):954-960",
        "title": "Validation of the 28-joint Disease Activity Score (DAS28) and European League Against Rheumatism response criteria based on C-reactive protein against disease progression in patients with rheumatoid arthritis, and comparison with the DAS28 based on erythrocyte sedimentation rate"
      },
      "formula": "das28_crp",
      "formula_expression": "DAS28(CRP) = 0.56*sqrt(tjc28) + 0.28*sqrt(sjc28) + 0.014*gh + 0.36*ln(crp_mg_l+1) + 0.96; Wells 2009; CRP mg/L; GH 0-100 mm VAS; remission DAS28<2.6; not DAS28-ESR; not SDAI; not CDAI; magent does not count joints or assay CRP",
      "score": 1.21,
      "crp_mg_l": 1.0,
      "sjc28": 0,
      "tjc28": 0,
      "das28_crp_band": "remission",
      "gh": 0.0
    },
    {
      "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": "Wells G, Becker JC, Teng J, Dougados M, Schiff M, Smolen J, Aletaha D, van Riel PLCM",
        "doi": "10.1136/ard.2007.084459",
        "id": "wells-2009",
        "pmid": "18490431",
        "source": "Ann Rheum Dis. 2009;68(6):954-960",
        "title": "Validation of the 28-joint Disease Activity Score (DAS28) and European League Against Rheumatism response criteria based on C-reactive protein against disease progression in patients with rheumatoid arthritis, and comparison with the DAS28 based on erythrocyte sedimentation rate"
      },
      "formula": "das28_crp",
      "formula_expression": "DAS28(CRP) = 0.56*sqrt(tjc28) + 0.28*sqrt(sjc28) + 0.014*gh + 0.36*ln(crp_mg_l+1) + 0.96; Wells 2009; CRP mg/L; GH 0-100 mm VAS; remission DAS28<2.6; not DAS28-ESR; not SDAI; not CDAI; magent does not count joints or assay CRP",
      "score": 1.21,
      "crp_mg_l": 1.0,
      "sjc28": 0,
      "tjc28": 0,
      "das28_crp_band": "remission",
      "gh": 0.0
    }
  ]
}

Response

Field Type Description
formula string das28_crp
formula_expression string Exact expression used
score number Wells 2009 DAS28(CRP), 2 decimals. 0.56*sqrt(tjc28)+0.28*sqrt(sjc28)+0.014*gh+0.36*ln(crp_mg_l+1)+0.96
das28_crp_band string Wells 2009 DAS28-defined remission when score < 2.6; otherwise not_remission. Does not apply EULAR 3.2/5.1 present-score cutoffs as single-visit activity bands.
tjc28 integer Tender 28-joint count used
sjc28 integer Swollen 28-joint count used
crp_mg_l number CRP in mg/L used
gh number General health 0-100 mm VAS used
citation object Wells et al. Ann Rheum Dis 2009 citation
disclaimer string Not-a-device notice

Example JSON

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

{
  "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": "Wells G, Becker JC, Teng J, Dougados M, Schiff M, Smolen J, Aletaha D, van Riel PLCM",
    "doi": "10.1136/ard.2007.084459",
    "id": "wells-2009",
    "pmid": "18490431",
    "source": "Ann Rheum Dis. 2009;68(6):954-960",
    "title": "Validation of the 28-joint Disease Activity Score (DAS28) and European League Against Rheumatism response criteria based on C-reactive protein against disease progression in patients with rheumatoid arthritis, and comparison with the DAS28 based on erythrocyte sedimentation rate"
  },
  "formula": "das28_crp",
  "formula_expression": "DAS28(CRP) = 0.56*sqrt(tjc28) + 0.28*sqrt(sjc28) + 0.014*gh + 0.36*ln(crp_mg_l+1) + 0.96; Wells 2009; CRP mg/L; GH 0-100 mm VAS; remission DAS28<2.6; not DAS28-ESR; not SDAI; not CDAI; magent does not count joints or assay CRP",
  "score": 1.21,
  "crp_mg_l": 1.0,
  "sjc28": 0,
  "tjc28": 0,
  "das28_crp_band": "remission",
  "gh": 0.0
}

Client errors (HTTP 400)

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

HTTP Code When
400 invalid_das28_crp DAS28-CRP inputs must match Wells 2009 28-joint counts, CRP mg/L, and 0-100 general health. 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

  • 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.
  • 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.
  • DAS28-ESR — Compute the Prevoo 1995 28-joint DAS with ESR from caller-assigned tender and swollen 28-joint counts, ESR in mm/h, and patient general health on a 0-100 mm VAS. Returns the published score only.

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.