RESUMO
Objective:To establish a candidate reference procedure for the enumeration of cell particles in urine and applied to the multi-center performance evaluation of an automated urine formed elements analyzer.Methods:According to the standardized mannual microscopic examination of fresh non-centrifuged urine samples and the recommended reference method for enumeration of cell particles in urine published by ISLH, we established a candidate reference procedure for the enumeration of cell particles in urine. From four class A tertiary hospitals′ clinical laboratories, three rigorous trained technicians per hospital tested the same specimen respectively using the reference procedure. Each specimen was repeatedly counted 5 times, obtaining the quantitative results of cell particles were obtained in urine. Four hospitals used the established candidate reference measurement procedure and the automated urine formed elements analyzer to detect 40 to 60 urine specimens from September 2020 to January 2021, and evaluate the established reference method, meanwhile evaluate the accuracy and consistency of the each count from automated urinalysis analyzer.Results:Using the candidate reference measurement procedures, the coefficient of variation of results derived from three trained technicians per hospital was less than 6.98% (red blood cells), 6.99% (white blood cells), 13.94% (epithelial cells) and met the quality requirements. The performance evaluation results of automated urine formed elements analyzer showed that the accuracy of red blood cells, white blood cells and epithelial cells met the requirements (bias≤4.98%) and was well consistent with the reference measurement procedure ( R2≥0.989). Conclusions:A candidate reference measurement procedure for the enumeration of urine cell particles was successfully established with satisfactory precision and accuracy. This procedure was applied to multicenter performance evaluation of an automated urine formed elements analyzer with good accuracy and consistency.