Background: The erythrocyte sedimentation rate (ESR) test is performed widely in laboratories. Besides the traditional Westergren method, new methods have been developed for ESR measurements. We aimed to compare the instruments using new methods, iSED (Alcor Scientific) and Ves-Matic Cube 200 (Diesse Diagnostica Senese, Italy) with the Westergren method. Methods: Blood samples from 136 patients were taken into EDTA tubes for automated analyzers and citrated tubes for Westergren method. Patients were divided into three groups-low, medium, and high-according to their sedimentation rates. Precision, stability, and interference studies of the methods were performed. Results: The iSED sedimentation method (n = 136) yielded a slope of (0.61-0.84), with an intercept of (-2.32 to 1.89), which resulted in a mean bias of 13; and the Ves-Matic Cube 200 method (n = 136) yielded a slope of (0.85-1.00), with an intercept of (0.00-3.07), which resulted in a mean bias of 1.4 in Passing-Bablok regression analysis compared to the reference method. Conclusion: iSED sedimentation showed a poor correlation and a high bias (>10%) with the Westergren method, and Ves-Matic Cube 200 method showed a higher correlation and a lower bias than the iSED device when compared with Westergren reference method. These instruments should be carefully monitored. (C) 2014 Wiley Periodicals, Inc.