Quantitative Urine Particle Analysis: Integrative Approach for the Optimal Combination of Automation with UF-100 and Microscopic Review with KOVA Cell Chamber

Abstract

Background: Automated systems have enabled the counting of particles in urine to be standardized. Their superiority over traditional sediment analysis has been well documented, but they have not gained wide acceptance. The reasons for this are that sediment analysis has been performed and interpreted for decades. Additionally, pathologic casts and other unknown particles still must be confirmed under the microscope. Furthermore, comparison between the methods has revealed outliers and thus decreased confidence in automation. Methods: We used the standardized KOVA cell chamber system to count particles and compared the results with UF-100 flow cytometry as an alternative to traditional sediment analysis. Results: We compared 252 randomly selected urine samples and obtained a review rate of 33%. Microscopic verification was necessary because of the presence of casts, yeast, sperm, dysmorphic erythrocytes, and some misclassified erythrocytes or leukocytes that were detected by incongruent dipstick results and abnormal scattergrams. We obtained correlation coefficients of 0.966 for erythrocytes and 0.935 for leukocytes. Criteria for an algorithm to identify samples that needed microscopic review were derived from comparisons between the number of particles from UF-100, dipstick results, cell chamber counting, and sediment analysis. Conclusions: Automated cell counting combined with microscopic counting with a standardized cell chamber system is useful. An objective algorithm for review criteria can be developed via systematic comparison of UF-100 flow cytometry and microscopy. Only urine

Automated urinalysis: first experiences and a comparison between the Iris iQ200 urine microscopy system, the Sysmex UF-100 flow cytometer and manual microscopic particle counting

“…Therefore, urine samples from patients suspected of suffering from nephritis must be analyzed by manual microscopy (26). Our results are consistent with findings of other studies showing that the UF-100 has greater deficits when analyzing samples with high numbers of crystals, yeast and sperm cells known to overlap with the erythrocyte gate in the scattergram (27,30,33).…”

“…In addition, pathological casts cannot be differentiated sufficiently. The identification of pathological casts requires confirmation by microscopic review, as already pointed out by others (26,27,30,33). Such particles are flagged by the UF-100 system.…”

“…Automation may be helpful in solving these problems and improves the accuracy and precision of urine sediment analysis. Several studies compared automated image-based analysis systems and/or flow cytometer-based systems with manual microscopy (6,(19)(20)(21)(22)(23)(24)(25)(26)(27), and most recognized the accuracy and precision of automated systems (28)(29)(30)(31)(32), as well as their feasibility as routine screening tools (8,10,17,18,33,34).…”

“…The UF-100, however, yields more false-positive results for leukocytes compared to the iQ200. In particular, naked epithelial cells or transitional cells can be misclassified as leukocytes (27,30). The total accuracy rates for the iQ200 tended to be higher than those of the UF-100.…”

Evaluation of urinalysis parameters to predict urinary-tract infection

“…The feasibility of a flow-cytometry urinalysis for selecting samples that require microscopic examination has been previously discussed [2][3][4][5]. We evaluated the individual parameters and crosschecked Sysmex UF-100 data with results obtained with dipstick testing and microscopic-inspection urinalysis to predict UTI, using the results of urine culture as a reference method.…”