Department of Laboratory Medicine, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China.
Department of Parasitology, The School of Basic Medical Sciences, Inner Mongolia Medical University, Hohhot, China.
PLoS One. 2023 Feb 1;18(2):e0281118. doi: 10.1371/journal.pone.0281118. eCollection 2023.
The screening performance of urine flow cytometry parameters (e.g., white blood cell and bacteria) for urinary tract infection (UTI) has been widely recognized. The majority of previous studies, however, investigated the screening performance of Sysmex UF-1000i urine flow cytometer. This study aimed to investigate the screening performance of Sysmex UF-5000 analyzer, a third-generation urinary flow cytometer, for UTI and its novel parameter named Gram flag for discriminating gram-positive and negative pathogens. Urine specimens sent to the clinical microbiology laboratory of our hospital for bacterial culture between September 13, 2021, and November 15, 2021, were prospectively and consecutively collected. The Sysmex UF-5000 analyzer was used to determine urine white blood cell (WBC) and bacteria simultaneously. A chemical strip was used to assess urine nitrate. UTI was defined as positive urine bacterial culture > 104 CFU /ml. The receiver operating characteristics (ROC) curve, nomogram, decision tree, and decision curve were used to determine the screening performance of urine WBC, nitrate, and bacterial. A total of 246 UTIs and 425 non-UTIs were enrolled. The areas under the ROC curve (AUCs) for WBC and bacterial were 0.74 and 0.86, respectively. The decision curve showed that urine bacteria had a higher benefit than WBC. The nomogram indicated that urine bacterial had the largest effect on the probability of UTI. The sensitivity and specificity of the decision tree were 0.69 and 0.95, respectively. The flag of Gram-negative had a positive predictive value (PPV) of 0.93 in patients with urine bacteria > 1367 /μl. Therefore, we conclude that urine bacteria determined by the Sysmex UF-5000 had higher screening performance and greater benefit than WBC. The decision tree can be used to improve the screening performance of routine urinary parameters. The flag of Gram-negative is a reliable indicator to confirm gram-negative bacteria infection in UTI patients.
尿液流式细胞术参数（如白细胞和细菌）在尿路感染（UTI）中的筛选性能已得到广泛认可。然而，大多数先前的研究都调查了 Sysmex UF-1000i 尿液流式细胞仪的筛选性能。本研究旨在研究第三代尿液流式细胞仪 Sysmex UF-5000 分析仪对 UTI 的筛选性能及其用于区分革兰阳性和阴性病原体的新型参数革兰氏菌标记。
2021 年 9 月 13 日至 11 月 15 日，前瞻性连续收集我院临床微生物实验室送检的用于细菌培养的尿液标本。同时使用 Sysmex UF-5000 分析仪检测尿液白细胞（WBC）和细菌。化学条带用于评估尿液硝酸盐。UTI 的定义为阳性尿液细菌培养> 104 CFU / ml。使用受试者工作特征（ROC）曲线、列线图、决策树和决策曲线来确定尿液 WBC、硝酸盐和细菌的筛选性能。共纳入 246 例 UTI 和 425 例非 UTI。WBC 和细菌的 ROC 曲线下面积（AUC）分别为 0.74 和 0.86。决策曲线显示尿液细菌比 WBC 具有更高的获益。列线图表明尿液细菌对 UTI 概率的影响最大。决策树的灵敏度和特异性分别为 0.69 和 0.95。当尿液细菌> 1367 / μl 时，革兰氏阴性菌标记的阳性预测值（PPV）为 0.93。
因此，我们得出结论，与 WBC 相比，Sysmex UF-5000 测定的尿液细菌具有更高的筛选性能和更大的获益。决策树可用于提高常规尿液参数的筛选性能。革兰氏阴性菌标记是确认 UTI 患者革兰氏阴性菌感染的可靠指标。
