尿流式有形成分及干化学分析在尿路感染诊断中的应用评价

目的 评价尿干化学分析及UF-1000i流式尿有形成分分析单独及联合应用时在尿路感染诊断中的应用价值.方法 留取148例尿路感染(UTI)患者、284例非尿路感染患者的中段尿标本,分别用培养法做尿细菌计数和鉴定,用UF-1000i流式尿有形成分分析仪做细菌计数(BACT)、酵母样菌(YEC)、WBC检测,用URISYS 2400尿干化学分析仪做自细胞酯酶(LEU)、亚硝酸盐(NIT)检测.评价尿干化学分析、UF-1000i流式尿有形成分分析仪以及UF-1000i联合尿干化学分析与定量尿细菌培养对诊断UTI的一致程度,并评价其对UTI诊断的敏感度、特异度、阳性预测值、阴性预测值、准确度.结果 在148例尿路感染患者中,定量尿细菌培养的检出率为73.6%(109/148),尿干化学分析LEU和NIT同时为阳性的检出率为26.4%(39/148),两种方法的检出率之间差异有统计学意义(χ2=55.68,P<0.05).UF-1000i流式尿有形成分分析BACT和WBC任意1项为阳性诊断UTI的检出率为91.2%(135/148),高于定量尿细菌培养的检出率,差异有统计学意义(χ2=14.70,P<0.05).UF-1000i流式尿有形成分分析和尿干化学分析仪联合参数BACT、WBC、LEU和NIT任意1项为阳性诊断UTI的检出率为94.6%(140/148),高于定量尿细菌培养的检出率,差异有统计学意义(χ2=20.45,P<0.05).尿干化学分析敏感度较低,为26.4%(39/148),特异度较高,为99.3%(282/284);应用UF-1000i流式尿有形成分分析BACT作为尿路感染诊断依据时的敏感度为92.6%(137/148),特异度为39.8%(113/284),阳性预测值为44.5%(137/308),阴性预测值为91.1%(113/124);尿干化学分析与UF-1000i流式尿有形成分分析联合应用时,敏感度为98.O%(145/148),阴性预测值97.1%(100/103),特异度为35.2%(100/284),阳性预测值为44.1%(145/329),准确度为56.7%(245/432).结论 联合UF-1000i流式尿有形成分分析及尿干化学分析可在早期尿路感染筛查诊断中发挥重要作用;同时对尿细菌培养为阴性的UTI患者的明确诊断具有重要价值.

Evaluation of urine analysis by flow cytometry and strip test in diagnosing urinary tract infection

Objective To evaluate the clinical application of automated urine formed elements analyzer and/or urine dipstick analyzer for examination of urinary formed elements in screening urinary tract infection (UTI). Methods 148 fresh midstream clear-catch urine samples from the UTI patients and 284 fresh midstream clear-catch urine samples from non-UTI subjects were selected. Bacteria culture was performed for bacterial colony counting and identification. Bacteria counts ( BACT), yeast-like fungus and WBC were performed by UF-looOi automated urine formed elements analyzer. Leukocyte esterase test (LEU) and nitrite test (NIT) were performed by URISYS 2400 urine dipstick analyzer. We evaluated data obtained from urine dipstick analyzer, UF-1000i and combination of UF-1000i with urine dipstick analyzer and the results was compared with those obtained from quantitative bacterial culture. Then we evaluated the sensibility, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. Results Among the 148 patients with UTI, the positive rate of the quantitative bacterial culture was 73.6% (109/148), the positive rate of LEU and NIT detected by dipstick test 26. 4% (39/148).There was significantly statistical difference between bacterial culture and strip test(χ2 = 55.68 ,P < 0. 05 ). The positive rate of urine flow cytometry by UF-1000i with either positive of BACT and WBC was 91.2%(135/148), which was higher than the positive rate of the quantitative bacterial culture. There was significant difference between two methods (χ2 = 14. 70, P < 0. 05 ). The positive rate of anyone positive among BACT, WBC, LEU and NIT was 94. 6% (140/148) when detected with combination of dipstick test and UF-1000i, which was higher than the positive rate of the quantitative bacterial culture. And there was significant difference between two methods (χ2 = 20. 45, P < 0. 05 ). The sensitivity of dipstick test was low (26. 4% ,39/148 ), and specificity was high ( 99. 3%, 282/284 ) . The sensitivity, specificity, positive predictive value, negative predictive value of BACT detected by UF-1000i in diagnosing urinary tract infection were 92. 6% ( 137/148 ), 39. 8% ( 113/284 ). 44. 5% ( 137/308 ) and 91.1% ( 113/124 ), respectively. If the dipstick test was combined with UF-1000i, the sensitivity, negative predictive value, specificity, positive predictive value and accuracy were 98.0% ( 145/148 ), 97.1% ( 100/103 ). 35.2% (100/284) ,44. 1% (145/329) and 56. 7% (245/432), respectively. Conclusions The combination of urine dipstick test and automated urine formed elements analyzer UF-1000i plays an important role in early diagnosis of UTI. And it has significant value in diagnosis of UTI, especially for the patients with negative bacterial cultures of urine sample.