Evaluation of an automated erythrocyte sedimentation rate analyzer as compared to the Westergren manual method in measurement of erythrocyte sedimentation rate

Context: Monitor 100 (Electa Lab, Italy) is a newly developed automated method for measurement of erythrocyte sedimentation rate (ESR). Aims: The aim of our study was to compare the ESR values by Monitor 100 against the standard Westergren method. Patients and Methods: This cross-sectional study was conducted at a Level I trauma care center on 200 patients. The samples taken were as per the recommendations charted out by International Council for Standardization in Hematology (ICSH) for comparing automated and manual Westergrens method. Statistical Analysis Used: Bland and Altman statistical analysis was applied for evaluating Monitor 100 against the conventional Westergren method. Results: The analysis revealed a low degree of agreement between the manual and automated methods especially for higher ESR values, mean difference -11.2 (95% limits of agreement, -46.3 to 23.9) and mean difference -13.4 (95% limits of agreement-58.9 to 32.1) for 1 and 2 hours, respectively. This discrepancy which is of clinical significance was less evident for ESR values in the normal range <25 mm/hour (-7.7 mean of difference; -18.9 to 3.5 limits of agreement). Conclusions: The fully automated system Monitor 100 for ESR measurement tends to underestimate the manual ESR readings. Hence it is recommended that a correction factor be applied for the range of ESR values while using this equipment. Further studies and validation experiments would be required.