2018 Volume 67 Issue 5 Pages 708-715
To standardize criteria for morphological classification and to quantify precision in urinary sediment examination, we developed an internal quality control (IQC) system using photos from Examination of Urinary Sediment 2010. Three staff members classify photos on a computer screen, and then the system measures their competence in terms of accuracy rate and predicted value. The aim of this study was to verify the competence of staff members in identifying urinary sediments and the quality improvement of intralaboratory error on competence after introducing the system. In urinary sediment components in which the accuracy rate or predicted value was under 60%, some listed components were different between staff members. An error between staff members was verified in clinical specimens by comparing the chi-square value and the number of positive results in each component. The long-term intralaboratory error showed that there were some components whose error decreased or increased immediately after introducing the system. Moreover, the number of components in which the intralaboratory error was detected decreased from 11 to 7 after using the system. These results indicate that our system quantified staff members’ competence and could have an influence on the intralaboratory error in clinical samples. The IQC system will contribute to standardizing the morphological classification and improving the quality of urinary sediment examination in our laboratory. However, its benefit may be limited for some components systematically identified on the basis of a patient’s background. Therefore, an assessment of those errors is needed using positive rates for those components in clinical specimens.
