ASDAS-CRP Calculator

Ankylosing Spondylitis Disease Activity Score with CRP

Patient Assessment

Back Pain

Patient-reported level of AS neck, back, or hip pain (0-10 scale)

Duration of Morning Stiffness

Patient-reported severity upon waking (0-10 scale)

Patient Global Assessment

Patient's perception of disease activity over the past week (0-10 scale)

Peripheral Pain/Swelling

Patient-reported pain/swelling in joints excluding neck, back, or hips (0-10 scale)

CRP (C-reactive Protein)

mg/L

Laboratory CRP value in mg/L

Formula

ASDAS-CRP =

(0.12 × Back Pain)

+ (0.06 × Morning Stiffness Duration)

+ (0.11 × Patient Global Assessment)

+ (0.07 × Peripheral Pain/Swelling)

+ (0.58 × ln(CRP + 1))

Variables:

Back Pain:Patient-reported (0-10 scale)
Morning Stiffness:Duration severity (0-10 scale)
Patient Global:Disease activity perception (0-10 scale)
Peripheral Pain:Joints excluding spine (0-10 scale)
CRP:CRP: C-Reactive Protein in mg/L (uses natural logarithm)

The logarithmic transformation of CRP (ln(CRP + 1)) receives the highest weighting coefficient (0.58), making it the most influential component of the score.

Result

Enter all values to calculate the ASDAS-CRP score

About

The ASDAS-CRP calculator helps clinicians track ankylosing spondylitis severity over time and guide treatment decisions.

Clinical Use

Use in patients with confirmed ankylosing spondylitis to assess disease activity and guide treatment decisions.

Clinical Context

ASDAS-CRP provides a composite measure of disease activity incorporating both patient-reported outcomes and objective inflammatory markers. It is particularly useful for:

Monitoring treatment response
Determining when to escalate or de-escalate therapy
Clinical trial endpoints
Standardized disease activity assessment

Limitations

Requires laboratory CRP measurement
Patient-reported measures may be subjective
May not capture all aspects of disease burden