尿浓缩对儿科尿路感染尿液分析诊断性能的重要性。

The Importance of Urine Concentration on the Diagnostic Performance of the Urinalysis for Pediatric Urinary Tract Infection.

机构信息

Division of Emergency Medicine, Boston Children's Hospital, Boston, MA; Harvard Medical School, Boston, MA.

出版信息

Ann Emerg Med. 2017 Jul;70(1):63-71.e8. doi: 10.1016/j.annemergmed.2016.11.042. Epub 2017 Feb 4.

DOI:10.1016/j.annemergmed.2016.11.042

PMID:28169050

Abstract

STUDY OBJECTIVE

The presence of leukocyte esterase by urine dipstick and microscopic pyuria are both indicators of possible urinary tract infection. The effect of urine concentration on the diagnostic performance of the urinalysis for pediatric urinary tract infection has not been studied. Our objective is to determine whether the urinalysis performance for detecting urinary tract infection varies by urine concentration as measured by specific gravity.

METHODS

This was a retrospective cross-sectional study of the urine laboratory results of children younger than 13 years who presented to the emergency department during 68 months and had a paired urinalysis and urine culture obtained. Urinary tract infection was defined as pure growth of a uropathogen at standard culture thresholds. Test characteristics were calculated across 4 specific gravity groups (1.000 to 1.010, 1.011 to 1.020, 1.021 to 1.030, and >1.030).

RESULTS

In total, 14,971 cases were studied. Median age was 1.5 years (interquartile range 0.4 to 5.5 years) and 60% were female patients. Prevalence of urinary tract infection was 7.7%. For the presence of leukocyte esterase and a range of pyuria cut points, the positive likelihood ratios decreased with increasing specific gravity. From most dilute to most concentrated urine, the positive likelihood ratio decreased from 12.1 (95% confidence interval [CI] 10.7 to 13.7) to 4.2 (95% CI 3.0 to 5.8) and 9.5 (95% CI 8.6 to 10.6) to 5.5 (95% CI 3.3 to 9.1) at a threshold of greater than or equal to 5 WBCs per high-power field and presence of leukocyte esterase, respectively. The negative likelihood ratios increased with increasing specific gravity for leukocyte esterase and microscopic pyuria.

CONCLUSION

For the detection of pediatric urinary tract infection, the diagnostic performance of both dipstick leukocyte esterase and microscopic pyuria varies by urine concentration, and therefore the specific gravity should be considered when the urinalysis is interpreted.

摘要

研究目的

尿液干化学法白细胞酯酶阳性和镜下脓尿均提示可能存在尿路感染。尿液浓缩对尿分析诊断儿童尿路感染的性能影响尚未研究。我们的目的是确定尿液分析检测尿路感染的性能是否因比重测量的尿液浓度而有所不同。

方法

这是一项回顾性横断面研究，纳入了 68 个月期间在急诊科就诊的年龄小于 13 岁的儿童的尿液实验室结果，这些儿童均进行了配对的尿液分析和尿液培养。尿路感染定义为标准培养阈值下单纯尿路病原体生长。在 4 个比重组（1.000 至 1.010、1.011 至 1.020、1.021 至 1.030 和>1.030）中计算了检测特性。

结果

共纳入 14971 例患者。中位年龄为 1.5 岁（四分位距 0.4 至 5.5 岁），60%为女性患者。尿路感染的患病率为 7.7%。对于白细胞酯酶的存在和一系列脓尿切点，阳性似然比随比重的增加而降低。从最稀释到最浓缩的尿液，阳性似然比从 12.1（95%置信区间[CI]10.7 至 13.7）降至 4.2（95%CI3.0 至 5.8）和 9.5（95%CI8.6 至 10.6）降至 5.5（95%CI3.3 至 9.1），分别在白细胞酯酶大于或等于 5 个高倍视野/白细胞和白细胞酯酶阳性的切点处。白细胞酯酶和镜下脓尿的阴性似然比随比重的增加而增加。