DAPSA Score Calculator
Estimate Disease Activity in Psoriatic Arthritis (DAPSA) using joint counts, patient-reported scores, and CRP.
Formula: DAPSA = TJC68 + SJC66 + Patient Pain (0–10) + Patient Global (0–10) + CRP (mg/dL)
What is DAPSA?
DAPSA stands for Disease Activity in Psoriatic Arthritis. It is a practical clinical score used to quantify disease activity in people with psoriatic arthritis (PsA). The score combines objective findings (tender and swollen joint counts, CRP) with patient-reported symptoms (pain and global assessment), producing one number that helps track inflammation over time.
Why a DAPSA calculator is useful
Psoriatic arthritis can fluctuate from week to week. A single, standardized number helps patients and clinicians discuss whether treatment is working, worsening, or stable. Using a calculator reduces manual errors and makes it easier to monitor trends between visits.
- Supports treat-to-target care plans
- Improves consistency between visits
- Allows quick interpretation with clear cutoffs
- Helps document progress in clinical notes
DAPSA interpretation thresholds
After calculating the score, classify disease activity with these common categories:
- Remission: DAPSA ≤ 4
- Low disease activity: DAPSA > 4 to ≤ 14
- Moderate disease activity: DAPSA > 14 to ≤ 28
- High disease activity: DAPSA > 28
How to use this calculator correctly
1) Enter joint counts
Use the 68-joint tender count and 66-joint swollen count as assessed during exam. Accurate counts are essential because they can strongly influence the final score.
2) Enter patient-reported VAS scores
Both pain and patient global assessment are entered on a 0–10 scale. Use the same scale format consistently at each visit.
3) Enter CRP and unit
Laboratories may report CRP in mg/dL or mg/L. This calculator accepts both and converts mg/L automatically, so the formula remains correct.
4) Review category, not just number
The disease activity category is often more clinically actionable than the raw number alone. Trending categories over time can help inform treatment discussions.
Example calculation
If a patient has TJC68 = 10, SJC66 = 6, pain = 5.5, global = 4.5, and CRP = 12 mg/L:
- CRP conversion: 12 mg/L = 1.2 mg/dL
- DAPSA = 10 + 6 + 5.5 + 4.5 + 1.2 = 27.2
- Interpretation: Moderate disease activity
Important limitations
DAPSA is valuable, but it does not capture every feature of psoriatic disease. It focuses on peripheral joint activity and may not fully reflect skin burden, enthesitis, dactylitis, axial symptoms, function, or quality of life. It should be interpreted alongside physical exam findings, imaging, and patient goals.
Clinical reminder
This page is for educational and tracking purposes and is not a substitute for medical diagnosis or treatment advice. Clinical decisions should be made by qualified healthcare professionals using full clinical context.