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Rheumatoid Arthritis SLE / Lupus SpA / PsA Sjogren's Scleroderma Myositis Vasculitis Crystal Arthropathy Osteoporosis

Most Used

Start with the tools you reach for most

The three highest-use calculators across rheumatology practice. Each opens directly.

Disease Activity Score (CRP)

Standard treat-to-target monitoring in RA. 28-joint counts, patient global VAS, and CRP via validated formula. Remission below 2.6. EULAR response criteria built in. Preferred over ESR version in most modern practice.

Fransen & van Riel, 2003→

SLE Disease Activity Index 2000

24 weighted features across 9 organ domains. Standard endpoint in belimumab BLISS, anifrolumab TULIP, and voclosporin AURORA trials. SRI-4 response defined as a 4-point reduction without PGA worsening.

Gladman et al., 2002→

AS Disease Activity Score

ASAS/EULAR 2022 preferred instrument for axial SpA over BASDAI. Combines back pain, morning stiffness, peripheral pain, patient global, and CRP. Inactive below 1.3. Very high activity at 3.5 or above.

Lukas et al., 2009→

Practice Tool

Prior Authorization Generator

Generate PA letters and draft denial appeals for biologics and JAK inhibitors across RA, SLE, PsA, axial SpA, and myositis. Structured by payer criteria, ready to customize.

Open Prior Auth Generator →

Rheumatoid Arthritis

Full RA suite in Hub →

🦸Classification

RA Classification Criteria

Joint distribution, serology, acute phase reactants, and duration. Score 6 of 10 classifies as definite RA.

Disease Activity Score (CRP)

Standard treat-to-target score. Remission below 2.6. EULAR response criteria built in.

Disease Activity Score (ESR)

ESR-based DAS28. Runs approx. 0.6 points higher than CRP version. Required for some biologic pathways.

Clinical Disease Activity Index

No labs required. TJC28 + SJC28 + physician global + patient global. Remission at 2.8.

Simplified Disease Activity Index

CDAI plus CRP in mg/dL. Simple linear sum. Note: uses mg/dL, not mg/L.

Patient-Reported Outcome

No joint exam or labs. Completes in under 60 seconds. Validated against DAS28.

Health Assessment Questionnaire

Gold standard functional disability measure. 8 domains. HAQ above 1.0 independently predicts mortality.

SLE / Lupus

Full SLE suite in Hub →

🔵Classification

SLE Classification Criteria

ANA entry criterion required. 8 weighted domains, max-only scoring. Score 10 or above classifies. Sensitivity 96%, specificity 93%.

SLE Disease Activity Index 2000

24 weighted features across 9 organ domains. Standard endpoint in BLISS, TULIP, and AURORA trials.

Physician Global Assessment (0-3 VAS)

Required component of SRI-4 and SRI-50. No worsening of PGA is part of the responder definition.

Spondyloarthritis & Psoriatic Arthritis

Full SpA/PsA suite in Hub →

🩹Classification

CASPAR Criteria

Psoriatic Arthritis

Score 3 or above with inflammatory articular disease classifies as PsA. Specificity above 98%.

🔩Classification

Axial SpA Criteria

ASAS Classification

Imaging arm (sacroiliitis + SpA feature) or clinical arm (HLA-B27 + 2 or more SpA features).

🦷Classification

Peripheral SpA Criteria

ASAS Classification

Entry via arthritis, enthesitis, or dactylitis. Set A (high-specificity features) or Set B (additive features).

AS Disease Activity Score

ASAS/EULAR 2022 preferred over BASDAI. Inactive below 1.3, very high at 3.5 or above.

Bath AS Disease Activity Index

6 patient-reported questions. Use when CRP is unavailable. Score 4 or above indicates active disease.

Disease Activity in PsA

TJC68 + SJC66 + pain VAS + global VAS + CRP. Remission at 4 or below. Primary endpoint in recent PsA trials.

Bath AS Functional Index

10 questions on daily function averaged for the score. Correlates with long-term work disability.

Vasculitis

Full vasculitis suite in Hub →

🌊Classification

ENT features, PR3-ANCA, granuloma. Score 5 or above classifies.

🔷Classification

MPO-ANCA, pulmonary fibrosis, pauci-immune GN. Score 5 or above classifies.

🔸Classification

Eosinophilia, airflow obstruction, nasal polyps. PR3-ANCA subtracts 3. Score 5 or above classifies.

🨀Classification

Age 50 or above required. Biopsy/US halo, ESR, jaw claudication, visual loss. Score 6 or above classifies.

🧋Classification

Takayasu Arteritis

Imaging evidence of large-vessel vasculitis required, age 60 or below. Score 5 or above classifies.

🮺Classification

ANCA-negative medium-vessel vasculitis. Livedo, orchitis, aneurysm on imaging. Score 5 or above classifies.

❄Classification

Cryoglobulinemic Vasculitis

Cryoglobulins, purpura, HCV, GN, biopsy deposits. Score 6 or above classifies.

Birmingham Vasculitis Activity Score

56 items across 9 organ systems. BVAS = 0 defines remission per RAVE and RITUXVAS.

Vasculitis Damage Index

64 items of irreversible organ damage since diagnosis. Higher VDI independently predicts mortality.

More Conditions

All remaining suites

For Sjogren's, Scleroderma, Myositis, Crystal Arthropathy, and Osteoporosis, open the Calculator Hub and select the condition tab.

Sjogren's Disease

Scleroderma (SSc)

Inflammatory Myositis

Crystal Arthropathy

Osteoporosis & Bone Health

Content reviewed by Mahiar Rabie, MS, MD · AutoimmuneCalc