Department of Pediatrics and Nephrology, Warsaw Medical University, 63A Żwirki and Wigury Street, 02-091, Warsaw, Poland.
Department of Laboratory Diagnostics and Clinical Immunology of Developmental Age, Warsaw Medical University, Warsaw, Poland.
Adv Exp Med Biol. 2018;1047:71-80. doi: 10.1007/5584_2017_107.
Early diagnosis of urinary tract infection (UTI) is challenging in infants due to unspecific symptoms, difficulty in urine collection and possible contamination. The aim of this study was to assesses the usefulness of serum and urine neutrophil gelatinase-associated lipocalin (sNGAL and uNGAL, respectively) in the diagnosis of febrile and non-febrile UTI in infants. This prospective observational study enrolled 66 infants with the first episode of UTI and 18 healthy controls. At the time of enrollment, sNGAL, uNGAL, urinalysis, urine culture, white blood cell count (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), and serum creatinine (sCr) were assessed. We found that, on average, both sNGAL and uNGAL levels were significantly higher in febrile UTI, compared to non-febrile UTI and controls. In turn, the mean sNGAL level, but not uNGAL, was significantly higher in the non-febrile UTI group compared to controls. sNGAL positively correlated with WBC, CRP, ESR and PCT, and uNGAL with CRP and leukocyturia. The receiver operating curves (ROC) demonstrate that the optimum cut-off of 76.2 ng/ml for sNGAL (sensitivity 92.9%, specificity 94.4%, and the area under the curve (AUC) of 0.98) and of 42.2 ng/ml for uNGAL (sensitivity 73.8%, specificity 72.2%, and AUC of 0.76) for diagnosing febrile UTI and 39.0 ng/ml for sNGAL (sensitivity 83.3%, specificity 55.6%, and AUC of 0.70) for diagnosing non-febrile UTI. In conclusion, serum NGAL is an excellent marker for the early diagnosis of febrile UTI, with sensitivity and specificity higher than those of urine NGAL. Diagnostic sensitivity of serum NGAL is smaller in non-febrile infants suffering from UTI, and urine NGAL is not useful for this purpose at all.
尿路感染（UTI）的早期诊断在婴儿中具有挑战性，因为其症状不具特异性，尿液收集困难且可能存在污染。本研究旨在评估血清和尿液中性粒细胞明胶酶相关脂质运载蛋白（sNGAL 和 uNGAL）在诊断婴儿发热和非发热性 UTI 中的作用。这项前瞻性观察性研究纳入了 66 例首次发生 UTI 的婴儿和 18 例健康对照者。在入组时，评估了 sNGAL、uNGAL、尿液分析、尿液培养、白细胞计数（WBC）、C 反应蛋白（CRP）、红细胞沉降率（ESR）、降钙素原（PCT）和血清肌酐（sCr）。我们发现，与非发热性 UTI 和对照组相比，发热性 UTI 患儿的 sNGAL 和 uNGAL 水平平均均显著升高。相反，与对照组相比，非发热性 UTI 组的平均 sNGAL 水平但不是 uNGAL 水平显著升高。sNGAL 与 WBC、CRP、ESR 和 PCT 呈正相关，uNGAL 与 CRP 和白细胞尿呈正相关。受试者工作特征曲线（ROC）显示，sNGAL 的最佳截断值为 76.2ng/ml（敏感性 92.9%，特异性 94.4%，曲线下面积（AUC）为 0.98），uNGAL 的最佳截断值为 42.2ng/ml（敏感性 73.8%，特异性 72.2%，AUC 为 0.76），用于诊断发热性 UTI；sNGAL 的最佳截断值为 39.0ng/ml（敏感性 83.3%，特异性 55.6%，AUC 为 0.70），用于诊断非发热性 UTI。结论：血清 NGAL 是诊断发热性 UTI 的优秀标志物，其敏感性和特异性均高于尿液 NGAL。患有 UTI 的非发热婴儿的血清 NGAL 诊断敏感性较小，尿液 NGAL 完全不适合用于此目的。
