Urinary tract infections in children: Testing a novel, noninvasive, point‐of‐care diagnostic marker

Abstract

Objectives: Urinary neutrophil gelatinase-associated lipocalin (uNGAL) appears highly accurate to identify urinary tract infections (UTIs) when obtained via catheterization.Our primary aim was to determine the agreement in uNGAL levels between paired catheter and bag urine specimens. Our secondary aim was to compare the diagnostic test characteristics of quantitative uNGAL, dipstick uNGAL (a potential point-of-care test), and urinalysis (UA). Methods:This was a prospective study of febrile children < 24 months evaluated for UTIs. We evaluated quantitative uNGAL at a previously identified threshold of 39.1 ng/mL, dipstick uNGAL at its built-in threshold of >50 ng/mL, and UA at standard thresholds for leukocyte esterase (LE). A positive urine culture was defined as >100,000 CFUs/mL of a pathogen.Results: A total of 211 patients were included (10% with positive urine cultures); 116 had paired catheterized and bagged samples. The agreement between catheterized and bagged samples at a quantitative uNGAL cutoff of ≥39.1 ng/mL was 0.76

Evaluation of diagnostic accuracy of urine neutrophil gelatinase-associated lipocalin in patients with symptoms of urinary tract infections: a meta-analysis

“…The risk of applicability concerns assessment of the same 25 included studies ( 5 , 36 – 59 ) was also performed according to the guidance of QUADAS-2. Sixteen studies were rated as having low risk of all three domain of applicability concerns ( 5 , 37 , 41 , 42 , 44 – 48 , 50 – 53 , 57 – 59 ). Seven studies were classified as having high risk of applicability concerns ( 36 , 38 – 40 , 43 , 49 , 54 ).…”

“…The forest plot shown in Figure 3A summarizes the log transformed uNGAL value in each study for the non-UTI samples reported in the pediatric studies. 16 non-UTI groups from 14 studies were included ( 37 , 39 , 40 , 42 , 44 – 48 , 50 , 51 , 53 , 55 , 57 ). Summarized mean and standard deviation were reported.…”

“…The estimated area under the curve (AUC) is 0.99. We estimated that the cut-off point of 48.43 ng/ml would optimize Youden Index with sensitivity of 96% and specificity of 97% ( 36 , 37 , 39 , 40 , 42 – 48 , 50 – 53 , 55 , 57 ).…”

Are Positive Urine Cultures Directly Correlated with Elevated Levels of Novel Biomarkers for Childhood Urinary Tract Infection?

“…Bagged urine samples exhibited lower quantitative and dipstick NGAL specificities than catheterised urine samples. 39 Other studies also established that urine NGAL expression temporally correlates with the bacterial stimulus, responds in a quantitative trend to the bacterial colony count, and rapidly reverses with the resolution of infection. [40][41][42] Furthermore, antimicrobial peptides (human α-defensin 5 [HD5] and human neutrophil peptides 1-3 [HNP1-3]) were recently evaluated for their diagnostic accuracy in children with culture-positive UTI.…”

“…43 These findings highlight, to some extent, the diagnostic utility of the biomarkers and their dependence on the urine-sampling method. 39 Urine HD5 and NGAL are more likely to correlate with UTI aetiologically attributed to E. coli than with UTI from other bacterial agents since pyuria frequently occurs in the former. 22 However, there is no consensus on the diagnostic value of these two biomarkers as they also exhibited poorer diagnostic utility in another study.…”