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🦴 ASAS Axial SpA Classification

UseWhen to use: chronic back pain with onset <45 years under rheumatology workup.

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StrataClassification supports SpA labeling — not automatic biologic start.

LimitsWhen not to use: without entry criteria. · Pitfall: counting features incorrectly around HLA-B27. · Correlate MRI reads with ASAS definitions.

SourceRudwaleit M et al. ASAS axial SpA criteria

Runs locally in your browser (no PHI uploaded). For licensed clinicians — not a substitute for clinical judgement.
Stored on this device for revisit reminders

This-shift next steps

After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.

Scene next step
📋rheumOpen scene pack →
Related scores
Matching pathway
🧭septic_arthritisOpen pathway →
Score + version; reference only — not a substitute for care · no HIS write

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Methodology · worked example, guidelines & full notes
Clinical takeaway

Entry first.

When to use

When to use: chronic back pain with onset <45 years under rheumatology workup.

How it works

Entry + (sacroiliitis ≥1 feature) OR (HLA-B27 + ≥2 features).

Key points

  • Entry first.
  • Two arms.
  • Next: ASDAS / BASDAI.

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: back pain ≥3 months AND age at onset <45 yearsNo
Sacroiliitis on imaging (MRI ASAS or definite radiographic)No
HLA-B27 positiveNo / unknown
Number of SpA features (IBP, arthritis, enthesitis heel, uveitis, dactylitis, psoriasis, IBD, NSAID response, SpA FH, HLA-B27, elevated CRP)0

→ASAS axSpAEntry not met

  • Entry：Needs back pain ≥3 mo + onset <45 y
Entry: back pain ≥3 months AND age at onset <45 yearsYes (required)
Sacroiliitis on imaging (MRI ASAS or definite radiographic)Yes
HLA-B27 positiveYes
Number of SpA features (IBP, arthritis, enthesitis heel, uveitis, dactylitis, psoriasis, IBD, NSAID response, SpA FH, HLA-B27, elevated CRP)0

→ASAS axSpADoes not classify

  • Cue：Neither imaging nor clinical arm met
Verification & sources · governance
FAQ

Frequently asked questions

Does ASAS Axial 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 Axial SpA Classification calculated in practice? Can you show a worked example?
Inputs: Entry: back pain ≥3 months AND age at onset <45 years No, Sacroiliitis on imaging (MRI ASAS or definite radiographic) No, HLA-B27 positive No / unknown, Number of SpA features (IBP, arthritis, enthesitis heel, uveitis, dactylitis, psoriasis, IBD, NSAID response, SpA FH, HLA-B27, elevated CRP) 0 → Result: ASAS axSpA Entry not met（Entry: Needs back pain ≥3 mo + onset <45 y） Inputs: Entry: back pain ≥3 months AND age at onset <45 years Yes (required), Sacroiliitis on imaging (MRI ASAS or definite radiographic) Yes, HLA-B27 positive Yes, Number of SpA features (IBP, arthritis, enthesitis heel, uveitis, dactylitis, psoriasis, IBD, NSAID response, SpA FH, HLA-B27, elevated CRP) 0 → Result: ASAS axSpA Does not classify（Cue: Neither imaging nor clinical arm met）
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