# ACR/EULAR RA classification criteria

ACR/EULAR RA

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/acr_eular_ra`
HTML: https://magentlab.com/docs/acr-eular-ra
Markdown: https://magentlab.com/docs/acr-eular-ra.md

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

## What it computes

Apply the 2010 ACR/EULAR rheumatoid arthritis classification criteria (Aletaha Table 3): require definite clinical synovitis, sum joint involvement, serology, acute-phase reactants, and symptom duration (max 10), and return whether score ≥6 or typical RA erosions classify RA. Not a diagnosis.

## When to use

When an agent already has caller-assigned Aletaha 2010 entry, joint-involvement category, serology row, APR, duration, alternative-diagnosis, and erosive-disease flags and needs the published classification result for research, not a diagnosis of RA, not 1987 ACR RA, and not SDAI.

## When not to use

- Not a medical device and not a diagnosis of rheumatoid arthritis. Classification criteria for research (Aletaha 2010). Not 1987 ACR RA. Not SDAI.
- Entry (clinical_synovitis true: at least one joint with definite clinical synovitis/swelling) must be met or the request is HTTP 400 and is not returned as classified=false.
- alternative_diagnosis_better true still returns the Table 3 score but classified is false (not the target population: synovitis better explained by another disease).
- erosive_disease_typical_of_ra true classifies even if score <6 (paper footnote: erosive disease typical of RA with a history compatible with prior fulfillment of the 2010 criteria).
- magent does not examine joints or titer RF/ACPA. Joint involvement is the caller-assigned highest Table 3 category (large = shoulders, elbows, hips, knees, ankles; small = MCP, PIP, 2nd–5th MTP, thumb IP, wrists; DIP, 1st CMC, 1st MTP excluded). Serology is the caller-assigned Table 3 row (high-positive RF or ACPA takes the high row).

## Formula

```
ACR/EULAR 2010 RA classification (Aletaha Table 3): required clinical_synovitis true (at least one joint with definite clinical synovitis/swelling; else do not score). Score = joint_involvement (one_large 0, two_to_ten_large 1, one_to_three_small 2, four_to_ten_small 3, gt_ten_with_small 5) + serology (negative 0, low_positive 2, high_positive 3) + abnormal_apr 1 + duration_ge_6_weeks 1; max 10. classified false if alternative_diagnosis_better; else true if erosive_disease_typical_of_ra or score ≥6. Not a diagnosis. Not 1987 ACR RA. Not SDAI
```

## Citation

[2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative](https://doi.org/10.1136/ard.2010.138461)
Aletaha D, Neogi T, Silman AJ, Funovits J, Felson DT, Bingham CO 3rd, Birnbaum NS, Burmester GR, Bykerk VP, Cohen MD, Combe B, Costenbader KH, Dougados M, Emery P, Ferraccioli G, Hazes JMW, Hobbs K, Huizinga TWJ, Kavanaugh A, Kay J, Kvien TK, Laing T, Mease P, Ménard HA, Moreland LW, Naden RP, Pincus T, Smolen JS, Stanislawska-Biernat E, Symmons D, Tak PP, Upchurch KS, Vencovský J, Wolfe F, Hawker G
Ann Rheum Dis. 2010;69(9):1580-1588
DOI: [10.1136/ard.2010.138461](https://doi.org/10.1136/ard.2010.138461)

## Worked example

### Four to ten small joints, high-positive serology, classified

Given: `abnormal_apr=true, alternative_diagnosis_better=false, clinical_synovitis=true, duration_ge_6_weeks=true, erosive_disease_typical_of_ra=false, joint_involvement=four_to_ten_small, serology=high_positive`

1. Required: clinical_synovitis true
2. four_to_ten_small 3 + high_positive 3 + abnormal_apr 1 + duration_ge_6_weeks 1
3. score = 8 (max 10) ≥6; classified true; band classified


### Score 5, not classified

Given: `abnormal_apr=false, alternative_diagnosis_better=false, clinical_synovitis=true, duration_ge_6_weeks=false, erosive_disease_typical_of_ra=false, joint_involvement=four_to_ten_small, serology=low_positive`

1. four_to_ten_small 3 + low_positive 2; APR and duration 0
2. score = 5 (max 10) <6; classified false; band not_classified


### Typical RA erosions classify below score 6

Given: `abnormal_apr=false, alternative_diagnosis_better=false, clinical_synovitis=true, duration_ge_6_weeks=false, erosive_disease_typical_of_ra=true, joint_involvement=two_to_ten_large, serology=negative`

1. two_to_ten_large 1; serology, APR, and duration 0
2. score = 1 (max 10) <6; erosive_disease_typical_of_ra true
3. classified true; band classified


### One large joint scores 0

Given: `abnormal_apr=false, alternative_diagnosis_better=false, clinical_synovitis=true, duration_ge_6_weeks=false, erosive_disease_typical_of_ra=false, joint_involvement=one_large, serology=negative`

1. one_large 0 + negative 0; APR and duration 0
2. score = 0 (max 10) <6; classified false; band not_classified


### High-positive serology scores 3

Given: `abnormal_apr=false, alternative_diagnosis_better=false, clinical_synovitis=true, duration_ge_6_weeks=false, erosive_disease_typical_of_ra=false, joint_involvement=one_large, serology=high_positive`

1. one_large 0 + high_positive 3; APR and duration 0
2. score = 3 (max 10) <6; classified false; band not_classified


## Also searched as

- ACR EULAR RA
- 2010 RA classification criteria
- Aletaha 2010 rheumatoid arthritis
- ACR/EULAR 2010 RA score
- not 1987 ACR RA
- RF ACPA RA classification
- erosive disease typical of RA
- joint involvement serology APR duration

## Parameters

- `clinical_synovitis` (boolean, required): Must be true. Aletaha 2010 entry: at least one joint with definite clinical synovitis (swelling) as assigned by the caller. false is invalid and is not classified=false. magent does not examine joints.
- `alternative_diagnosis_better` (boolean, required): Synovitis better explained by another disease (Aletaha 2010 target population). true still returns the Table 3 score but classified is false. magent does not assign an alternative diagnosis.
- `erosive_disease_typical_of_ra` (boolean, required): Erosive disease typical of RA with a history compatible with prior fulfillment of the 2010 criteria (Aletaha 2010 footnote). true classifies even if score <6. magent does not read films.
- `joint_involvement` (string, required): Caller-assigned highest Aletaha 2010 Table 3 joint-involvement category. magent does not count joints. Large = shoulders, elbows, hips, knees, ankles. Small = MCP, PIP, 2nd–5th MTP, thumb IP, wrists. DIP, 1st CMC, and 1st MTP are excluded. one_large scores 0; two_to_ten_large scores 1; one_to_three_small (with or without large) scores 2; four_to_ten_small (with or without large) scores 3; gt_ten_with_small (>10 joints, at least 1 small) scores 5.
- `serology` (string, required): Caller-assigned Aletaha 2010 Table 3 serology row (at least one RF or ACPA test). High-positive RF or ACPA takes the high row. negative scores 0; low_positive scores 2; high_positive scores 3. magent does not titer RF or ACPA.
- `abnormal_apr` (boolean, required): Abnormal CRP or ESR as assigned by the caller (Aletaha 2010 Table 3). true scores 1; false (normal CRP and ESR) scores 0. magent does not assay CRP or ESR.
- `duration_ge_6_weeks` (boolean, required): Duration of symptoms ≥6 weeks as assigned by the caller (Aletaha 2010 Table 3). true scores 1; false scores 0. magent does not date symptom onset.

## 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/acr_eular_ra`
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": [
    {
      "abnormal_apr": "true",
      "alternative_diagnosis_better": "false",
      "clinical_synovitis": "true",
      "duration_ge_6_weeks": "true",
      "erosive_disease_typical_of_ra": "false",
      "joint_involvement": "four_to_ten_small",
      "serology": "high_positive"
    },
    {
      "abnormal_apr": "true",
      "alternative_diagnosis_better": "false",
      "clinical_synovitis": "true",
      "duration_ge_6_weeks": "true",
      "erosive_disease_typical_of_ra": "false",
      "joint_involvement": "four_to_ten_small",
      "serology": "high_positive"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/acr-eular-ra

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/acr_eular_ra",
  "items": [
    {
      "band": "classified",
      "components": [
        {
          "value": "four_to_ten_small",
          "factor": "joint_involvement",
          "points": 3,
          "present": true
        },
        {
          "value": "high_positive",
          "factor": "serology",
          "points": 3,
          "present": true
        },
        {
          "factor": "abnormal_apr",
          "points": 1,
          "present": true
        },
        {
          "factor": "duration_ge_6_weeks",
          "points": 1,
          "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, Neogi T, Silman AJ, Funovits J, Felson DT, Bingham CO 3rd, Birnbaum NS, Burmester GR, Bykerk VP, Cohen MD, Combe B, Costenbader KH, Dougados M, Emery P, Ferraccioli G, Hazes JMW, Hobbs K, Huizinga TWJ, Kavanaugh A, Kay J, Kvien TK, Laing T, Mease P, Ménard HA, Moreland LW, Naden RP, Pincus T, Smolen JS, Stanislawska-Biernat E, Symmons D, Tak PP, Upchurch KS, Vencovský J, Wolfe F, Hawker G",
        "doi": "10.1136/ard.2010.138461",
        "id": "aletaha-2010",
        "pmid": "20699241",
        "source": "Ann Rheum Dis. 2010;69(9):1580-1588",
        "title": "2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative"
      },
      "formula": "acr_eular_ra",
      "formula_expression": "ACR/EULAR 2010 RA classification (Aletaha Table 3): required clinical_synovitis true (at least one joint with definite clinical synovitis/swelling; else do not score). Score = joint_involvement (one_large 0, two_to_ten_large 1, one_to_three_small 2, four_to_ten_small 3, gt_ten_with_small 5) + serology (negative 0, low_positive 2, high_positive 3) + abnormal_apr 1 + duration_ge_6_weeks 1; max 10. classified false if alternative_diagnosis_better; else true if erosive_disease_typical_of_ra or score ≥6. Not a diagnosis. Not 1987 ACR RA. Not SDAI",
      "max_score": 10,
      "score": 8,
      "classified": true
    },
    {
      "band": "classified",
      "components": [
        {
          "value": "four_to_ten_small",
          "factor": "joint_involvement",
          "points": 3,
          "present": true
        },
        {
          "value": "high_positive",
          "factor": "serology",
          "points": 3,
          "present": true
        },
        {
          "factor": "abnormal_apr",
          "points": 1,
          "present": true
        },
        {
          "factor": "duration_ge_6_weeks",
          "points": 1,
          "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, Neogi T, Silman AJ, Funovits J, Felson DT, Bingham CO 3rd, Birnbaum NS, Burmester GR, Bykerk VP, Cohen MD, Combe B, Costenbader KH, Dougados M, Emery P, Ferraccioli G, Hazes JMW, Hobbs K, Huizinga TWJ, Kavanaugh A, Kay J, Kvien TK, Laing T, Mease P, Ménard HA, Moreland LW, Naden RP, Pincus T, Smolen JS, Stanislawska-Biernat E, Symmons D, Tak PP, Upchurch KS, Vencovský J, Wolfe F, Hawker G",
        "doi": "10.1136/ard.2010.138461",
        "id": "aletaha-2010",
        "pmid": "20699241",
        "source": "Ann Rheum Dis. 2010;69(9):1580-1588",
        "title": "2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative"
      },
      "formula": "acr_eular_ra",
      "formula_expression": "ACR/EULAR 2010 RA classification (Aletaha Table 3): required clinical_synovitis true (at least one joint with definite clinical synovitis/swelling; else do not score). Score = joint_involvement (one_large 0, two_to_ten_large 1, one_to_three_small 2, four_to_ten_small 3, gt_ten_with_small 5) + serology (negative 0, low_positive 2, high_positive 3) + abnormal_apr 1 + duration_ge_6_weeks 1; max 10. classified false if alternative_diagnosis_better; else true if erosive_disease_typical_of_ra or score ≥6. Not a diagnosis. Not 1987 ACR RA. Not SDAI",
      "max_score": 10,
      "score": 8,
      "classified": true
    }
  ]
}
```

## Response fields

- `formula` (string): acr_eular_ra
- `formula_expression` (string): Aletaha 2010 ACR/EULAR RA classification expression
- `score` (integer): Aletaha 2010 Table 3 points. Integer 0–10.
- `max_score` (integer): 10
- `classified` (boolean): false if alternative_diagnosis_better; else true if erosive_disease_typical_of_ra or score ≥6. Classification criteria for research, not a diagnosis of RA. Not 1987 ACR RA. Not SDAI.
- `band` (string): classified when classified is true; not_classified otherwise. Not a diagnosis. Not 1987 ACR RA. Not SDAI.
- `components` (array): Per-item Aletaha 2010 Table 3 points
- `citation` (object): Aletaha 2010 Ann Rheum Dis citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "band": "classified",
  "components": [
    {
      "value": "four_to_ten_small",
      "factor": "joint_involvement",
      "points": 3,
      "present": true
    },
    {
      "value": "high_positive",
      "factor": "serology",
      "points": 3,
      "present": true
    },
    {
      "factor": "abnormal_apr",
      "points": 1,
      "present": true
    },
    {
      "factor": "duration_ge_6_weeks",
      "points": 1,
      "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, Neogi T, Silman AJ, Funovits J, Felson DT, Bingham CO 3rd, Birnbaum NS, Burmester GR, Bykerk VP, Cohen MD, Combe B, Costenbader KH, Dougados M, Emery P, Ferraccioli G, Hazes JMW, Hobbs K, Huizinga TWJ, Kavanaugh A, Kay J, Kvien TK, Laing T, Mease P, Ménard HA, Moreland LW, Naden RP, Pincus T, Smolen JS, Stanislawska-Biernat E, Symmons D, Tak PP, Upchurch KS, Vencovský J, Wolfe F, Hawker G",
    "doi": "10.1136/ard.2010.138461",
    "id": "aletaha-2010",
    "pmid": "20699241",
    "source": "Ann Rheum Dis. 2010;69(9):1580-1588",
    "title": "2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative"
  },
  "formula": "acr_eular_ra",
  "formula_expression": "ACR/EULAR 2010 RA classification (Aletaha Table 3): required clinical_synovitis true (at least one joint with definite clinical synovitis/swelling; else do not score). Score = joint_involvement (one_large 0, two_to_ten_large 1, one_to_three_small 2, four_to_ten_small 3, gt_ten_with_small 5) + serology (negative 0, low_positive 2, high_positive 3) + abnormal_apr 1 + duration_ge_6_weeks 1; max 10. classified false if alternative_diagnosis_better; else true if erosive_disease_typical_of_ra or score ≥6. Not a diagnosis. Not 1987 ACR RA. Not SDAI",
  "max_score": 10,
  "score": 8,
  "classified": true
}
```

## Errors

- HTTP 400 `invalid_acr_eular_ra`: clinical_synovitis must be true; joint_involvement one_large, two_to_ten_large, one_to_three_small, four_to_ten_small, or gt_ten_with_small; serology negative, low_positive, or high_positive (Aletaha 2010 ACR/EULAR RA Table 3). 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_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.
- [SDAI](https://magentlab.com/docs/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.
- [Leiden UA rule](https://magentlab.com/docs/leiden-arthritis) — 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.

- 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.