Ankylosing Spondylitis Disease Activity Score with CRP (ASDAS-CRP)
ASDAS-CRP Calculator
mg/L
Score:–
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Stratifies severity of ankylosing spondylitis (AS) using clinical and laboratory data, specifically CRP.
Why Use
The ASDAS-CRP is the preferred disease activity index according to the Assessment of SpondyloArthritis international Society (ASAS). May be useful for trending disease activity over time.
Formula
ASDAS-CRP = (0.12 x back pain) + (0.06 x morning stiffness) + (0.11 x patient global assessment of disease activity) + (0.07 x peripheral pain/swelling) + (0.58 x ln(CRP + 1)) Where variables are: Back pain Ask the patient: "How would you describe the overall level of AS neck, back, or hip pain you have had?" Morning stiffness Ask the patient: "How would you describe the overall level of morning stiffness you have had from the time you wake up?" Patient global assessment of disease activity Ask the patient: "How active was your spondylitis, on average, during the last week?" Peripheral pain/swelling Ask the patient: "How would you describe the overall level of pain/swelling in joints other than neck, back, or hips you have had?" CRP C-reactive protein, mg/L All variables, except CRP, should be graded on a scale of 0 (least severe) to 10 (most severe).
Pearls / Pitfalls
Other than CRP, all values are self-reported by the patient and therefore subjective.
Advice
May be useful in helping to guide treatment decisions; e.g. detecting improvement with TNF inhibitors.
More Information
Interpretation: ASDAS-CRP Disease activity <1.3 Inactive 1.3-2.0 Low 2.1-3.5 High >3.5 Very high