2017 Volume 66 Issue 3 Pages 255-265
We have examined the basic analytical performance of the urine flow cytometer UF-5000 (Sysmex) in comparison with its previous model, UF-1000i, and with microscopic examination (urine sediment). 1,300 urine samples were collected in Kanazawa Medical University Hospital for this study and the rate of concordance, sensitivity, and specificity were calculated as the performance indices to compare their performances. The five essential parameters, namely, red blood cell count, white blood cell count, epithelial cell count, number of cast, and bacterial cell count, and the seven new parameters, namely, pathological cast, crystal, yeast, sperm, hyaline cast, squamous cell, and nonsquamous cell, were used in this study. From the comparison study among microscopic examination and the two analyzers, we found that UF-5000 showed a better performance index than UF-1000i in almost all the parameters. In particular, the performance indices of casts, hyaline casts, and pathological casts were improved in UF-5000 by better classification from mucus as follows. For casts, the sensitivity was 89.4% (77.2% in UF-1000i) and the specificity was 51.9% (48.3%). For hyaline casts, the sensitivity was 84.1% (50.3%). For pathological casts, the sensitivity was 92.9% (78.6%), and the specificity was 73.1% (58.9%). RBC also showed better improvements owing to better differentiation from its interference such as crystals and yeasts. Therefore, the concordance rate was 92.1% (89.7%), the sensitivity was 90.8% (86.7%), and the specificity was 90.3% (88.7%). When we examined 17 samples that showed discrepancy between UF-1000i and UF-5000 in essential parameters, the results of UF-5000 were similar to the results of microscopic examination in 15 samples. We found that UF-5000 shows better performance than UF-1000i owing to the decreased false positivity rate caused by interference particles such as mucus and crystals.
