Analytical Agreement Between the Vision C Automated ESR Analyzer and the Manual Westergren Reference Method: A...

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Biomarker Analysis

Background:

• Erythrocyte sedimentation rate (ESR) is a key biomarker for systemic inflammation.
• The Westergren method is the reference standard, but automated analyzers offer clinical advantages.
• Methodological differences between analyzers and the Westergren method can cause bias.

Purpose of the Study:

• To evaluate the analytical agreement between the Vision C automated ESR analyzer and the Westergren reference method.
• To assess bias and correlation across different ESR ranges.
• To determine if the Vision C analyzer meets established total error criteria.

Main Methods:

• Prospective, single-center study adhering to CLSI EP09-ED3 guidelines.
• 228 adult patients' ESR levels were analyzed using both Vision C (EDTA) and Westergren (sodium citrate) methods.
• Agreement assessed via Bland-Altman analysis, Passing-Bablok regression, Pearson correlation, and RCPA TEa.

Main Results:

• A significant mean bias of -3.30 mm/h was observed, with bias increasing at higher ESR values (heteroscedasticity).
• Strong overall correlation (r=0.961) was found, though it decreased in higher ESR subgroups.
• The Vision C analyzer met RCPA allowable total error (TEa) criteria across all tested ranges, including high ESR levels.

Conclusions:

• The Vision C analyzer demonstrates a level-dependent negative bias compared to Westergren, particularly at higher ESRs.
• Despite the bias, strong correlation and TEa compliance support its suitability for routine clinical use.
• Method-specific reporting and consistent instrument use are recommended, with further study suggested for high ESR ranges.