Comparative Analysis of Erythrocyte Sedimentation Rate Measured by Automated and Manual Methods in Anaemic Patients

Abstract

Purpose Erythrocyte sedimentation rate (ESR) is a widely used indicator of inflammation and a routinely done hematology investigation to monitor patients of autoimmune and infectious diseases. We aimed to compare the ESR results obtained by Roller 20LC automated instrument and standard reference Westergren method and analyzed the effect of anemia (hematocrit) on ESR measurements through the automated method. Methods We analyzed 1377 random anemic OPD patients (hematocrit [HCT] < 35%) for ESR levels measured by Roller 20LC using EDTA blood and Westergren method using citrated blood for a one and half year period from January 1, 2018 to June 30, 2019. Fabry’s formula was used to correct the Westergren ESR. Results The total number of samples after evaluation were divided into low (n = 232), intermediate (n = 417), high (n = 406), and very high range of ESR (≥100 mm/hr; n = 422). Mean difference between values of corrected and automated ESR for the low, intermediate, high and very high ESR range was 2.33 ± 5.03, 10.95 ± 8.04, 28.22 ± 19.11 and 43.3 ± 19.22 mm/hr, respectively. The 95% limit of agreement calculated by the Bland–Altmann analysis between the two methods for low-ESR range was −7.53 to 12.2 (highest correlation coefficient –0.65), while for very high ESR, range was −5.1 to 81.5 (least coefficient of 0.18) (p < 0.001). Conclusion In laboratories with high-sample load and where manual measurement may be tedious, the automated method of ESR measurement can safely replace the Westergren method for low-ESR values in patients with low hematocrit. While for high-ESR values, validation by the standard Westergren method may be needed.

Keywords

• corrected esr
• hematocrit
• fabry’s formula
• anemia