Comparison of Red Blood Cell Parameter on UF-5000 Automated Urine Sediment Analyzer with DRBC by Phase Contrast Microscope

Abstract

Phase contrast microscope (PCM) analysis of red blood cells (RBCs) in urinalysis is used

to determine the cause of hematuria. Identifying dysmorphic red blood cells (DRBCs) in urine indicates that the RBCs are leaked from the nephron’s glomerulus. However classification of urine DRBCs by PCM is time-consuming and requires expertise. Clinical laboratories usually employ fully automated instruments for routine urinalysis. UF-5000 is an automated urinalysis instrument based on fluorescence flow cytometry providing RBCs information. In this study, we compared the RBC parameters of UF-5000; UF-%sRBCs, UF-small RBC/large RBC, UF-small RBC, UF-large RBC, UF-NL RBC, UF-lysed RBC, UF-RBC-P70Fsc, and UF-RBC-Fsc-DW with the identification of DRBCs by PCM using the receiver operating characteristic (ROC) curve analysis. The results revealed that the area under the curve (AUC) of the UF-small RBC, UF-RBC-Fsc-DW, UF-lysed RBC, and UF-NL RBC were statistically significant (p < 0.005) for detection of DRBCs. The UF-small RBC showed the largest AUC at 0.667, with a sensitivity of 60.22%, a specificity of 67.31%, a PPV of 45.2%, and an NPV of 79.1% at the cut off > 53.5/μL. In addition, the UF5000 also provides a UF-flag (RBC : mixed?, RBC : dysmorphic?) having a sensitivity of 91.40% and specificity of 26.92%. Combining the UF-small RBC parameter and the UF-DRBCs flag resulted in the sensitivity and specificity of 96.15% and 43.48%, respectively. In conclusion, a fully automated urine analyzer is a reduced workload and time-saving alternative for clinical laboratory identification of urine DRBCs.