2010 ACR/EULAR Rheumatoid Arthritis Classification Criteria Calculator
2010 ACR/EULAR Rheumatoid Arthritis Classification Criteria Calculator
Score the four 2010 ACR/EULAR domains out of 10, with the synovitis entry condition enforced rather than assumed — and with what classification criteria are actually for.
2010 ACR/EULAR RA criteria
Entry condition + 4 domains → 0–10Definite synovitis in several joints, not better explained by another disease. Six swollen small joints of the hands, rheumatoid factor 42 IU/mL against an upper limit of normal of 20 (so low-positive), CRP 21 mg/L, symptoms for 3 months
Four domains, maximum 10
- Target population
- at least one joint with definite clinical synovitis (swelling) not better explained by another disease
- Joint involvement
- any joint swollen or tender on examination indicating active synovitis, excluding the DIP joints, first CMC and first MTP
- Low-positive
- above the laboratory’s upper limit of normal but at or below 3 × ULN
- High-positive
- above 3 × the laboratory’s upper limit of normal
- Duration
- the patient’s self-report of the longest duration of synovitis symptoms in any currently involved joint
- Threshold
- “a score of 6 or greater being indicative of the presence of definite RA”
Worked example
Definite synovitis in several joints, not better explained by another disease. Six swollen small joints of the hands, rheumatoid factor 42 IU/mL against an upper limit of normal of 20 (so low-positive), CRP 21 mg/L, symptoms for 3 months
Entry condition met — definite clinical synovitis, nothing else explains it better
Six small joints → the 4–10 small joints category → 3
RF 42 IU/mL is above the ULN of 20 but not above 3 × 20 = 60 → low-positive → 2
CRP 21 mg/L is abnormal → 1
Symptoms 3 months, which is ≥6 weeks → 1
3 + 2 + 1 + 1 = 7 of 10 → 6 or more → classifies as definite RA
The 2010 ACR/EULAR criteria in full
| Domain | Category | Points |
|---|---|---|
| Joint involvement | 1 large joint | 0 |
| Joint involvement | 2–10 large joints | 1 |
| Joint involvement | 1–3 small joints (with or without involvement of large joints) | 2 |
| Joint involvement | 4–10 small joints (with or without involvement of large joints) | 3 |
| Joint involvement | >10 joints (at least one small joint) | 5 |
| Serology | Negative RF and negative ACPA | 0 |
| Serology | Low-positive RF or low-positive ACPA | 2 |
| Serology | High-positive RF or high-positive ACPA | 3 |
| Acute-phase reactants | Normal CRP and normal ESR | 0 |
| Acute-phase reactants | Abnormal CRP or abnormal ESR | 1 |
| Duration of symptoms | Less than 6 weeks | 0 |
| Duration of symptoms | 6 weeks or more | 1 |
Which joints count, and which do not
| Group | Joints | Note |
|---|---|---|
| Large | Shoulders, elbows, hips, knees, ankles | Scored, but a large joint alone can never reach the threshold — 2–10 large joints is 1 point |
| Small | Wrists, MCPs, PIPs, thumb IPs, 2nd–5th MTPs | These carry the weight. Four or more of them is 3 points |
| Excluded | DIP joints, first carpometacarpal, first MTP | “often affected by osteoarthritis” — counting them would classify hand OA as RA |
| Not examined | Any joint not assessed | The score uses swelling or tenderness on examination; imaging may supplement but the count is clinical |
What the criteria are for, and what they are not for
| Classification criteria (this page) | Clinical diagnosis | |
|---|---|---|
| Purpose | Assemble homogeneous, comparable cohorts for research | Decide what is wrong with one patient |
| Designed for | “newly presenting individuals with undifferentiated inflammatory synovitis” | Anyone in the clinic |
| Optimised for | Specificity — a study must not enrol patients who do not have the disease | Not missing a treatable disease |
| Output | Classified or not classified | A diagnosis, a differential, or a plan to look again |
| A score of 5 | Not classified, today | Tells you nothing decisive either way |
| Who applies it | An investigator, against a protocol | A clinician, against a patient |
Why the entry condition is a gate on this page and not a footnote
The 2010 ACR/EULAR criteria replaced the 1987 ARA criteria for one reason: the 1987 set described established rheumatoid arthritis — nodules, erosions, symmetrical deformity — and by the time a patient met it the window for preventing joint damage had largely closed. The 2010 set was built to classify patients early, which is why three of its four domains are things you can have in the first six weeks of illness. It is scored out of 10 across joint involvement, serology, acute-phase reactants and symptom duration, and 6 classifies as definite RA.
None of that arithmetic applies to a patient outside the target population, and this is where the criteria are most often misused. The 2010 criteria apply only to a patient with at least one joint showing definite clinical synovitis that is not better explained by another disease. Both halves matter. Without swelling — real synovitis found by an examiner, not pain reported by the patient — there is nothing for the criteria to classify, and tenderness alone in the joint count will not rescue that. And without the second half, the criteria will happily classify psoriatic arthritis, systemic lupus, a parvovirus arthritis or polyarticular gout as rheumatoid arthritis, because a seropositive patient with several swollen small joints and a raised CRP reaches 6 points whatever is actually causing the synovitis. That is why this page refuses to give a classification when the entry question is answered “No” rather than printing the total with a caveat underneath it.
The serology domain is the one that needs a laboratory rather than a bedside, and it is scored in multiples of the local upper limit of normal rather than in absolute units. Negative is at or below the ULN; low-positive is above it but no more than three times it; high-positive is above three times it. That means the same numerical result can score 2 in one laboratory and 3 in another, so the ULN has to come from the report rather than from memory — the anti-CCP converter and the rheumatoid factor converter will put a result into the units your laboratory’s interval is quoted in. One footnote in the original that implementations regularly drop: where rheumatoid factor is reported only as positive or negative, with no titre, a positive result scores as low-positive, never high.
The acute-phase domain is worth one point and is the cheapest to get wrong, because an ESR that is “normal” on a fixed adult reference interval may be abnormal for the patient’s age and sex — the age-adjusted ESR upper limit is the right comparator in an older patient, and it can flip this domain from 0 to 1. Finally, a note on what comes after classification. These criteria say nothing about how active the disease is or whether treatment is working; that is a different instrument entirely, and on this site it is the DAS28-ESR or the DAS28-CRP score. This supports a clinician’s judgement rather than replacing it. It is arithmetic on the figures entered, and it knows nothing about the patient in front of you.
Frequently asked questions
What score is needed to classify rheumatoid arthritis?
Six or more of a possible 10 points, in a patient who already has at least one joint with definite clinical synovitis not better explained by another disease. Aletaha et al describe “a score of 6 or greater being indicative of the presence of definite RA”.
Can the 2010 criteria be used to diagnose rheumatoid arthritis in an individual?
No, and the authors say so. The working group “deliberately labelled these criteria as ‘classification criteria’ as opposed to ‘diagnostic criteria'”. They exist to build comparable research cohorts. Clinicians diagnose and treat rheumatoid arthritis in patients who score below 6, and a score of 5 is not a reason to withhold treatment.
Which joints are counted, and which are excluded?
Large joints are the shoulders, elbows, hips, knees and ankles. Small joints are the wrists, MCP joints, PIP joints, thumb IP joints and 2nd–5th MTP joints. The DIP joints, the first carpometacarpal joint and the first MTP joint are excluded because they are “often affected by osteoarthritis”.
What counts as low-positive versus high-positive serology?
It is relative to the laboratory’s own upper limit of normal. Negative is at or below the ULN; low-positive is above the ULN but at or below three times it; high-positive is above three times it. Where rheumatoid factor is reported only as positive or negative, a positive result is scored as low-positive.
What happens if a patient scores fewer than 6 points?
They cannot be classified as having definite RA today, but the criteria are designed to be applied again as the illness evolves — the paper states that such a patient “might fulfil the criteria at a later time point”. Erosions typical of RA count as “prima facie evidence”, and a patient with long-standing disease who can be shown retrospectively to have met the criteria can be classified on that basis.
Does the symptom duration mean time since diagnosis?
No. It is “the patient’s self-report of the maximum duration of signs or symptoms of synovitis (pain, swelling and tenderness) of any joint that is clinically involved at the time of assessment” — so it starts when the joint symptoms started, not when the patient was referred or seen.
Related calculators
References
- Aletaha D, Neogi T, Silman AJ, et al. 2010 rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum. 2010;62(9):2569–81.
- Aletaha D, Neogi T, Silman AJ, et al. 2010 rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis. 2010;69(9):1580–8.
- Arnett FC, Edworthy SM, Bloch DA, et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum. 1988;31(3):315–24.
- Smolen JS, Landewé RBM, Bergstra SA, et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update. Ann Rheum Dis. 2023;82(1):3–18.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.