Automated measurement of the erythrocyte sedimentation rate: method validation and comparison

Abstract

Background Development of automated analyzers for erythrocyte sedimentation rate (ESR) has imposed the need for extensive validation prior to their implementation in routine practice, to ensure comparability with the reference Westergren method. The aim of our study was to perform the analytical validation of two automated ESR analyzers, the Ves-Matic Cube 200 and the TEST1. Methods Validation was performed according to the recent International Council for Standardization in Hematology recommendations and included determination of intrarun and inter-run precision, assessment of sample carryover, hemolysis interference, sensitivity to fibrinogen, method comparison with the gold standard Westergren method and stability test. Results The highest intrarun imprecision was obtained for the low ESR range (33.5% for Ves-Matic Cube; 37.3% for TEST1) while inter-run coefficients of variation on three levels were much better for the TEST1 (0%, 2% and 1.2%) compared to the Ves-Matic Cube 200 on two levels (24.9% and 5.8%). Both Ves-Matic Cube 200 and TEST1 showed no statistically significant difference when compared with Westergren. Bland-Altman analysis yielded overall insignificant mean biases for all comparisons, but a wider dispersion of results and 95% limits of agreement for comparisons including the Ves-Matic Cube 200. Carryover was considered insignificant, while hemolysis had a negative effect on all assessed ESR methods. The highest sensitivity to fibrinogen was observed for the Ves-Matic Cube 200, followed by Westergren and the least sensitive was the TEST1. Conclusions The obtained results proved the analytical validity of the TEST1 and the Ves-Matic Cube 200, and high comparability with the gold standard Westergren method, showing obvious improvements in standardization of ESR methods.

Analytical validation of the iSED automated analyzer for erythrocyte sedimentation rate

“…Hereby, we demonstrated a much better precision of iSED with commercial control samples at both evaluated levels than in a previously published study, while patient samples yielded intrarun CVs similar to already reported data for iSED, with decreasing precision at medium and low ESR levels This is in concordance with data from a lot of validation studies of automated ESR analyzers, regardless of the analyzer type and measurement principle and can be attributed to small numbers rather than poor analytical performance, therefore not being considered clinically significant.…”

“…Still, we believe that, in the era of increased implementation of automated ESR systems, our study can be useful as a starting point for laboratory professionals that are willing to transit to the use of alternate ESR analyzers. Automation of ESR analysis is being attractive as it poses many advantages in comparison with the Westergren method, including analysis from the EDTA sample, easier manipulation and enhanced personnel safety, higher reproducibility of results, and availability of quality control …”

“…The obtained result is transformed to Westergren values. The first result is obtained within 5 minutes, with a subsequent release every 20 seconds …”

Accuracy study of a novel alternate method measuring erythrocyte sedimentation rate for prototype hematology analyzer Celltac α+

“…The accuracy performance 8 of Novel ESR was evaluated by comparability 18 to the Reference WG and the comparative Modified WG for linearity 17 covering the AMI 19 . Reference WG and Novel ESR were measured from 271 samples and Modified WG from 240 samples and Passing‐Bablok regression analysis performed.…”

“…The validity of fibrinogen as an additive was confirmed by correlation evaluation in clinical samples 20 . Inflammation markers were compared with the Reference WG 8 and their validity assessed 18 . The validity of the additive (fibrinogen) as an inflammation marker was assessed: 28 samples with CRP and fibrinogen, and 22 samples with albumin and globulin were selected as factors correlated with ESR measurement 21 .…”