Comparison of the diagnostic performance of two automated urine sediment analyzers with manual phase-contrast microscopy.

Abstract

Background Recently, several manufacturers have launched automated urinalysis platforms. This study aimed to compare the diagnostic performance of the UF-5000 (Sysmex Corporation, Kobe, Japan) and the cobas® u 701 (Roche Diagnostics, Rotkreuz, Switzerland) urine sediment analyzers with manual phase-contrast microscopy as the reference method. Methods A total of 195 urine samples were analyzed on both automated platforms and subjected to manual microscopic examination. Agreement was assessed by Cohen's kappa (κ) analysis. Sensitivities and specificities were calculated. Results The agreement of the UF-5000 with manual microscopy was almost perfect (κ > 0.8) for red (RBC) and white blood cells (WBC), renal tubular epithel cells, hyaline casts, bacteria (BACT) and yeast (YLC), substantial (κ = 0.61-0.80) for squamous epithel cells (SEC) and pathologic casts, and moderate (κ = 0.41-0.60) for transitional epithel cells. The cobas® u 701 showed substantial agreement (κ = 0.61-0.80) for WBC, moderate agreement (κ = 0.41-0.60) for hyaline casts, and fair agreement (κ = 0.21-0.40) for RBC, SEC, non-squamous epithel (NEC), pathologic casts, BACT and YLC. The UF-5000 sensitivities ranged between 98.5% for RBC and 83.3% for pathological casts. The cobas® u 701 showed sensitivities between 83.0% for WBC and 31.6% for YLC. Conclusions The UF-5000 (Sysmex) analyzer showed a better diagnostic agreement with manual phase-contrast microscopy compared to the cobas® u 701 (Roche) module. The Sysmex platform showed reliable results for urine sediment analysis. However, pathological samples should be verified with manual microscopy.