Test 1 analyser for determination of ESR. 1. Practical evaluation and comparison with the Westergren technique

Abstract

Background: various modifcations of the Erythrocyte Sedimentation Rate (ESR) determination have been suggested since the original Westergren procedure that has been adopted as the gold standard by the International Council for Standardization in Haematology (ICSH). Recently, an automated method, (Alifax Test 1), based on a technique completely different from Westergren, has been introduced. Material and methods: In this comparative study, ESR of blood from 680 patients with various rheumatic diseases was determined on both Test 1 and the StaRRsed automated ESR analyser which performs measurements in accordance with ICSH specifcations. Furthermore the robustness of the new technique was evaluated. Results: Direct correlation of Test 1 and StaRRsed measurements confrmed the results of previous studies: an overall correlation coeffcient of R = 0.90. However, further statistical analysis showed that, depending on the instrument that was used, in 78 samples (i.e. 11.5%) the results could lead to different treatment suggestions. Furthermore it appeared that several procedural factors could infuence the fnal Test 1 outcome. Conclusions: Due to its sensitivity for procedural variations, Test 1 measurements should be carried out under strictly standardized conditions. Especially at the higher ESR levels the Test 1 technique is, however, not a reliable alternative for the ICSH approved ‘Westergren’ method.

Key Words::

• Erythrocyte sedimentation rate
• blood sedimentation
• laboratory instrumentation
• Westergren, methodology

Declaration of interest: None of the authors is supported, either financially or by other means, by any of the companies involved. The first author (MRH) is an external scientific adviser of R&R Mechatronics, B.V.