Performance Comparison of Urine Sediment Analytical Tool by Flowcytometry and Digital Imaging with Standardized Manual Microscopic Testing

Background: Urine sediment examination provides numerous information about patient's kidney condition. Flowcytometry and digital imaging system could conduct automatic urine sediment analysis. Therefore, determining the diagnostic performance of the examination is very important in the management carried out by the clinician. This study aims to determine the diagnostic performance of urine flowcytometry and digital imaging sediment examination tools compared to manual microscopes that are standardized as gold standards. Methods: This study is an analytical observational study with a cross-sectional approach on 92 urine samples of patients who attended the Internal Medicine Nephrology Polyclinic of Dr. Soetomo Academic Hospital Surabaya. The performance of flowcytometry and digital imaging methods is assessed by calculating sensitivity and specificity. Analysis of the suitability of each urine sediment parameter used Cohen's kappa. Urine sediment analysis with a light microscope was conducted with the Shih-Yung method as a gold standard. Results: The erythrocyte parameters revealed a very favorable result with the concordance of the flowcytometry with the Shih-Yung method (κ=0.82) and fair results for WBC (κ=0.25), Epithelium (κ=0.57) and Cast (κ=0.27). At the same time, yeast had substantial conformity (κ=0.63). The digital imaging method showed substantive fit for WBC (κ=0.676), RBC (κ=0.621), fair for SEC (κ=0.42) and NSE (κ=0.24), moderate for Yeast (κ=0.45), and slight for Hyaline Cast (κ=0.074) and Path Cast (κ= 0.134) Conclusion: The urine flowcytometry demonstrates better performance compatibility with a standardized manual microscope compared to urine digital imaging. However, pathological samples should still be verified with a manual microscope.