Quality Improvement of Urinalysis Results Based on Automatic Sediment Urinalysis and Urine Strip Results

ABSTRACT

BACKGROUND: Microscopic examinations are usually performed to confirm urine sediments in samples flagged in automated urinalysis. The aim of this study was to analyze the review rates and the difference in urinalysis results according to review rules. METHODS: A total of 1,408 urine samples submitted for health screening were collected. The urine chemistry test and urine sediment test were performed using EikenUS 3100 (Eiken Chemical Co. Ltd., Japan) and Sysmex UF-1000i (Sysmex Co., Japan), respectively. We assessed the rate of agreement between the 2 analyses and the kappa values for white blood cells (WBCs) and red blood cells (RBCs). Microscopic examinations were performed for all cases of discordant results between the urine strip and automated sediment analysis, some cases of concordant results, and cases of albuminuria. RESULTS: The review rate was 14.3%. Microscopic examinations were additionally performed on 77 samples (77/1,207, 6.4%) including 29 and 56 samples flagged for WBCs and RBCs, respectively. Based on the results of microscopic examination, the false-positive and the false-negative results of the urine chemistry test and automatic sediment analysis were corrected. Among concordant results between two methods, a clinically significant number of false-negatives were identified (6 results of WBC detection [6/125, 4.8%] and 4 of RBC detection [4/145, 2.8%]). Among the 22 unflagged cases of albuminuria, pathologic casts were detected in 21 cases (21/22, 95.5%). CONCLUSIONS: Microscopic examination based on the combined results of the two analyses improved the quality of the test.