Introduction: The C-reactive protein (CRP) to albumin (ALB) ratio (CAR) has emerged as a novel inflammatory biomarker. Aim of the work: This study was designed to detect the C-reactive protein/Albumin Ratio (CAR) as a new biomarker in Axial SpondyloArthritis and its relation to disease activity. Subjects and Methods: This study was Cross sectional study conducted on 72 Axial SpA patients attending the inpatient and outpatient clinics of Rheumatology and Rehabilitation Department, Faculty of Medicine, Zagazig university hospitals after taking a written consent and after review and approval by the Institutional Review Board (IRB) Committee during a period of six months from February to August 2022. Results: there was a statistical significance increase in mean CAR among active compared to non-active cases (3.41±3.38) ;(2.09±1.91) respectively. There was a statistically significant +ve correlation between CAR and BASDAI, BASFI, ESR and CRP. Also, there was a statistically significant -ve correlation between CAR and albumin among the studied cases. Conclusion: CAR was increased in axSpA of the active group. It was an independent predictive factor for axSpA disease activity and may be a novel and reliable biomarker for assessing the disease activity of axSpA patients.

Axial SpondyloArthritis (axSpA); C-reactive protein (CRP); C-reactive protein/Albumin Ratio (CAR); biomarker