🦴 ASAS Peripheral SpA Classification
UseWhen to use: arthritis/enthesitis/dactylitis under rheumatology workup.
StrataClassification supports SpA labeling — not automatic biologic start.
LimitsWhen not to use: without arthritis/enthesitis/dactylitis entry. · Pitfall: mixing axial-only presentations without peripheral entry. · Use CASPAR/DAPSA when psoriasis-dominant arthritis.
SourceRudwaleit M et al. ASAS peripheral SpA criteria
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
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Methodology · worked example, guidelines & full notes
Entry first.
When to use
When to use: arthritis/enthesitis/dactylitis under rheumatology workup.
How it works
Entry + (≥1 of uveitis/psoriasis/IBD/infection/B27/sacroiliitis) OR (≥2 other SpA features).
Key points
- Entry first.
- Two arms.
- Next: DAPSA / axial ASAS if back pain.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Entry: current peripheral arthritis AND/OR enthesitis AND/OR dactylitis | No |
|---|---|
| Uveitis (ever) | No |
| Psoriasis (ever) | No |
| Crohn / ulcerative colitis (ever) | No |
| Preceding infection (reactive arthritis context) | No |
| HLA-B27 positive | No / unknown |
| Sacroiliitis on imaging (MRI ASAS or definite radiographic) | No |
| Arthritis (as SpA feature tally item) | No |
| Enthesitis (as SpA feature tally item) | No |
| Dactylitis (as SpA feature tally item) | No |
| Inflammatory back pain ever | No |
| Family history of SpA | No |
→ASAS pSpAEntry not met
- Entry：Needs arthritis and/or enthesitis and/or dactylitis
| Entry: current peripheral arthritis AND/OR enthesitis AND/OR dactylitis | Yes (required) |
|---|---|
| Uveitis (ever) | Yes |
| Psoriasis (ever) | Yes |
| Crohn / ulcerative colitis (ever) | Yes |
| Preceding infection (reactive arthritis context) | Yes |
| HLA-B27 positive | Yes |
| Sacroiliitis on imaging (MRI ASAS or definite radiographic) | Yes |
| Arthritis (as SpA feature tally item) | Yes |
| Enthesitis (as SpA feature tally item) | Yes |
| Dactylitis (as SpA feature tally item) | Yes |
| Inflammatory back pain ever | Yes |
| Family history of SpA | Yes |
→ASAS pSpAClassifies
- Arm(s)：≥1 major SpA feature (uveitis/psoriasis/IBD/infection/B27/sacroiliitis) + ≥2 other SpA features
Verification & sources · governance
FAQ
Frequently asked questions
- Does ASAS Peripheral SpA Classification upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is ASAS Peripheral SpA Classification calculated in practice? Can you show a worked example?
- Inputs: Entry: current peripheral arthritis AND/OR enthesitis AND/OR dactylitis No, Uveitis (ever) No, Psoriasis (ever) No, Crohn / ulcerative colitis (ever) No, Preceding infection (reactive arthritis context) No, HLA-B27 positive No / unknown, Sacroiliitis on imaging (MRI ASAS or definite radiographic) No, Arthritis (as SpA feature tally item) No… → Result: ASAS pSpA Entry not met（Entry: Needs arthritis and/or enthesitis and/or dactylitis） Inputs: Entry: current peripheral arthritis AND/OR enthesitis AND/OR dactylitis Yes (required), Uveitis (ever) Yes, Psoriasis (ever) Yes, Crohn / ulcerative colitis (ever) Yes, Preceding infection (reactive arthritis context) Yes, HLA-B27 positive Yes, Sacroiliitis on imaging (MRI ASAS or definite radiographic) Yes, Arthritis (as SpA feature tally item) Yes… → Result: ASAS pSpA Classifies（Arm(s): ≥1 major SpA feature (uveitis/psoriasis/IBD/infection/B27/sacroiliitis) + ≥2 other SpA features）