INTRODUCTION: The International Council for Standardization in Haematology recommends that new methods and instruments used in medical laboratories be thoroughly tested with an analytical performance evaluation prior to implementation. This study is an assessment of the analytical performance characteristics of the Vision C analyzer (Shenzhen YHLO Biotech Co., Ltd., Shenzhen, China), which uses a modified Westergren method to measure erythrocyte sedimentation rate (ESR) and a comparison with the reference Westergren method.
METHODS: The analytical performance of the Vision C was evaluated according to intra-run/inter-run precision, stability, and compatibility with the gold standard Westergren method. In all, 173 patient samples were studied using both methods. The Westergren method levels were used to form 3 groups: <40, 40-80, and >80 mm/hour.
RESULTS: The intra-run precision ranged from 4.93% to 18.18% for 5 samples at different levels. Inter-run precision for the normal level was 7.03% and 2.94% for the pathological level. Both the room temperature and refrigerated samples were stable at 4 hours. The overall bias between the Westergren method and the Vision C analyzer was -5.23 mm/hour (confidence interval [CI]: -6.66 to -3.79), the correlation coefficient was 0.948, and the Passing-Bablok regression equation was y=2.073+0.805x. The bias of the Vision C for ESR values <40 mm/hour was -0.885 (CI: -2.027 to 0.258), -9.23 (CI: -11.853 to -6.613) for values 40-80 mm/hour, and -17.26 (Cl: -21.306 to -13.227) for values >80 mm/hour.
DISCUSSION AND CONCLUSION: The Vision C analyzer using a modified Westergren method met the precision and sample stability criteria, but the results were not fully compatible with the Westergren method at all ESR levels, and the difference was significant at high ESR levels.