Three-way comparison of different ESR measurement methods and analytical performance assessment of TEST1 automated ESR analyzer.

OBJECTIVES

Validation and performance assessment of novel ESR analyzer is required before implementation. The objective of this study was to assess the correlation between three ESR measurement methods. Full validation and performance assessment of an alternate method (TEST1) were also evaluated.

METHODS

Three-way correlation assessment for the Westergren (WG), modified Westregren (Mixrate), and alternate (TEST1) methods were performed. Analytical performance of TEST1 including precision, carryover, sample stability, potential interferences as well as effect of hematocrit (Hct) and mean corpuscular volume (MCV) were also determined.

RESULTS

Strong correlation between three ESR measurement methods were observed. Correlation coefficient (r) was 0.902, 0.977, and 0.949 for WG vs. TEST1, WG vs. Mixrate, and TEST1 vs. Mixrate, respectively with absolute bias <5 mm. For TEST1, precision and carryover were within the manufacturer's claim. Samples were stable upto 24 h and 48 h when they were stored at room temperature or 2-8 °C, respectively. No effect of trigyceride and cholesterol was observed. In low Hct samples, no significant different between the results obtained from Fabry's formula corrected WG values and from TEST1.

CONCLUSIONS

Three-way comparison study yielded a strong correlation between methods. As part of the method validation before implementing a new analyzer, full validation of TEST1 showed that all validated parameters met the manufacturer's specifications. A negative bias was observed but remains within the acceptable criteria. Difference in values for samples with low hematocrit were noted, but these can be corrected by Fabry's formula applied to the values from WG method.