Evaluation of FUS-2000 urine analyzer: analytical properties and particle recognition

This study evaluates the performance of microscopic part of a hybrid analyzer FUS-2000 (Dirui Industrial Co., Changchun, China), its analytical properties and particle recognition. The evaluation of trueness, repeatability, detection limit, carry-over, linearity range and analytical stability was performed according to Dirui protocol guidelines designed by Dirui Company to guarantee the quality of the instrument. Trueness for low, medium and high-value concentrations was calculated with bias of 15.5, 4.7 and -6.6%, respectively. Detection limit of 5 Ery/μl was confirmed. Coefficient of variation of 11.0, 5.2 and 3.8% was measured for within-run repeatability of low, medium and high concentration. Between-run repeatability for daily quality control had coefficient of variation of 3.0%. Carry-over did not exceed 0.05%. Linearity was confirmed for range of 0-16,000 particles/μl (R² = 0.9997). The analytical stability had coefficient of variation of 4.3%. Out of 1258 analyzed urine samples, 362 positive were subjected to light microscopy urine sediment analysis and compared to the analyzer results. Cohen's kappa coefficients were calculated to express the concordance. Squared kappa coefficient was 0.927 (red blood cells), 0.888 (white blood cells), 0.908 (squamous epithelia), 0.634 (transitional epithelia), 0.628 (hyaline casts), 0.843 (granular casts) and 0.623 (bacteria). Single kappa coefficients were 0.885 (yeasts) and 0.756 (crystals), respectively. Aforementioned results show good analytical performance of the analyzer and tight agreement with light microscopy of urine sediment.