Using urine nitrite sticks to test for urinary tract infection in children aged < 2 years: a meta-analysis

• Published in: Pediatric nephrology (Berlin, West) Vol. 34; no. 7; pp. 1283 - 1288
• Main Author: Coulthard, Malcolm G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2019; Springer; Springer Nature B.V
• Subjects: Adolescent; Age Factors; Analysis; Child; Child, Preschool; Children; Diagnosis; Diagnostic equipment (Medical); Humans; Infant; Infant, Newborn; Infants; Medical diagnosis; Medicine; Medicine & Public Health; Meta-analysis; Nephrology; Nitrites; Nitrites - analysis; Original; Original Article; Pediatric research; Pediatrics; Sensitivity and Specificity; Urinalysis - methods; Urinary tract; Urinary tract diseases; Urinary tract infections; Urinary Tract Infections - diagnosis; Urinary Tract Infections - urine; Urine; Urogenital system; Urology; Urine; Urinary tract infection; Stick testing; Bacteria; Diagnosis; Nitrite; Child; Culture
• ISSN: 0931-041X; 1432-198X; 1432-198X
• DOI: 10.1007/s00467-019-04226-6

Background This study aimed to determine whether nitrite sticks are as sensitive at detecting urinary tract infection (UTI) in children <2 years as they are in older children. Methods I reanalysed data on using nitrite sticks to detect UTIs for children aged either < 2 or 2–18 years. For sensitivity, evidence of a UTI was defined as level 1 when a single uropathogen grew ≥ 10 5 colony forming units/ml (cfu/ml) in two urine samples, level 2 when just one sample was cultured or a threshold of < 10 5  cfu/ml was used, and level 3 if mixed growths or Staphylococcus albus was considered to be positive. For specificity, children were defined as uninfected if they had 1 sterile urine culture. I also reanalysed our previously published data by age. Results The sensitivity was lower for children aged < 2 years (11 studies, 1321 subjects) than for older children (9 studies, 295 subjects), whether the level-1 values or all the studies were analysed (Fisher’s exact test, p  < 0.0001 for both). The level-1 sensitivities were 0.23 in the infants and 0.81 among older children (odds ratio = 0.07, 95% confidence interval 0.03–0.18). The specificity was very high in infants (10 studies, 1783 cases) and older children (7 studies, 5952 cases), at 0.990 and 0.996. Conclusions Nitrite sticks only have a 23% sensitivity in children aged < 2 years, so cannot reliably rule out UTIs. A positive nitrite stick test is about 99% likely to indicate a UTI in children of any age.