Comparison of erythrocyte sedimentation rate by Alifax Roller 20 LC method and standard Westergreen method

Erythrocyte sedimentation rate (ESR) is the most common test done for diagnosis and follow up treatment in patients suffering from autoimmune disorders and chronic illness. It is imperative for clinicians to understand the methodology, limitations and variations in testing platforms for ESR from ICSH standardized Westergreen method to various automated testing techniques. We conducted a retrospective study of 150 patients who were tested for ESR using Westergreen method and new automated Alifax Roller 20LC. The data was analyzed by applying Pearsons coefficient of correlation and Bland Altman analysis. It was observed that the automated Alifax Roller 20LC system tends to estimate ESR with positive bias. The maximum agreement between two methods was observed for ESR values between 20-40 mm/hr. As the likelihood of two similar results between two methods is uncertain, the difference between values should be acceptable clinically before replacing the ICSH Westergreen method with any new automated system.