CRD summary

This review concluded urine dipsticks were more effective for diagnosing urinary tract infection in children over two years than younger children, and reported no significant in performance between dipsticks and microscopy. However, data pertinent to these statements came from only two studies and one study, respectively. As the review also had methodological limitations, the authors' conclusions should be viewed cautiously.

Authors' objectives

To assess the effect of age on the diagnostic performance of urine dipstick testing for urinary tract infection in children, and to compare the performance of dipsticks with that of microscopy.

Searching

MEDLINE, EMBASE, the Cochrane Library, and CINAHL were searched (1966 to May 2009). The search strategy was reported in an online appendix (see URL for Additional Data). No language restrictions were applied, but studies that were not in English were only translated where they were considered highly relevant to the clinical question, or where there was a lack of English language research. There was no systematic attempt to identify unpublished studies.

Study selection

Studies that included both leucocyte esterase and nitrite dipstick testing, and compared dipstick testing with microscopy, for the diagnosis of urinary tract infection in children, were eligible for inclusion in the review. Included studies were required to use urine culture as the reference standard. Studies were excluded if they were in children with significant pre-existing uropathy, underlying renal disease, urinary catheters in situ, neurogenic bladder, immunosuppression, and children or neonates in intensive care.

The age of study participants varied; three studies were conducted in infants (under two years old) and the remainder included older children (up to 21 years). Included studies used a number of different proprietary dipstick tests (listed in the review). Diagnostic accuracy data were reported for two definitions of dipstick positive (nitrite or leucocyte esterase positive; and nitrate plus leucocyte esterase positive). Two thresholds for positive microscopy were considered: more than 5 wbc/hpf (white blood cells per high power field) for pyuria and few bacteria for bacteriuria; more than 10 wbc/hpf for pyuria and moderate bacteria for bacteriuria. The threshold for a positive diagnosis of urinary tract infection, using the reference standard, was 10³ or 10⁵ CFU/mL (colony forming units per mL), where reported.

Studies were independently assessed for inclusion by two reviewers.

Assessment of study quality

The authors stated that methodological quality of included studies was assessed using the NICE hierarchy of evidence for the performance of diagnostic tests, based on the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool; no further details of quality assessment were reported.

The authors did not state how many reviewers performed the quality assessment.

Data extraction

Data were extracted on the positive and negative likelihood ratios (LRs) for urine dipstick testing, where a positive test was nitrite plus leucocyte esterase positive, and where a positive test was either nitrite or leucocyte esterase positive.

The authors did not state how many reviewers performed the data extraction.

Methods of synthesis

A bivariate random-effects model was used to estimate summary diagnostic measures (sensitivity and specificity), not reported, and 95% confidence intervals. Summary positive and negative likelihood ratios were then calculated for the different tests and thresholds assessed. Models included a test for interaction by age.

Subgroup analyses were conducted for older (one year or older) and younger (under one year) children.

Results of the review

Six studies (total number of participants not reported) were included in the review. Only one study assessed the performance of both urine dipstick testing and microscopy.

For all six studies, the pooled positive likelihood ratio for leucocyte esterase plus nitrite positive was 34.61 95% (CI 17.81 to 63.33) and the corresponding negative likelihood ratio was 0.47 (95% CI 0.35 to 0.64). For leucocyte esterase or nitrite positive, the positive likelihood ratio was 5.11 (95% CI 3.00 to 8.70) and the corresponding negative likelihood ratio was 0.15 (95% CI 0.08 to 0.29).

The test for interaction by age was significant (p=0.01) where a positive test was defined as nitrite plus leucocyte esterase positive, but was not significant where a positive test was defined as nitrite or leucocyte esterase positive.

Subgroup analyses suggested that a test using leucocyte esterase plus nitrite positive to define urinary tract infection-positive, performed less well in younger children (mainly infants); the positive likelihood ratio was 7.62 (95% CI 0.95 to 51.85) and the corresponding negative likelihood ratio was 0.88 (95% CI 0.66 to 1.00), based on two studies. In older children, the positive likelihood ratio for this test was 38.54 (95% CI 22.49 to 65.31) and the corresponding negative likelihood ratio was 0.40 (95% CI 0.34 to 0.47), also based on two studies.

The single study that compared both microscopy and dipstick testing with the reference standard of urine culture, showed no significant difference between the two tests.

Authors' conclusions

Urine dipstick testing was more effective for the diagnosis of urinary tract infection in children over two years than for younger children.

CRD commentary

The review provided a clearly stated research question and defined appropriate inclusion criteria. A number of sources were searched for relevant studies, but inclusion restrictions meant that the possibility of language bias remained. The authors stated that they did not search for unpublished studies, raising the possibility of language bias. The possibility that relevant studies may have been omitted was particularly important given the small number of included studies and the even smaller number of studies that provided data to directly address the stated research questions. Measures were taken, during the study selection process, to minimise the potential for error and/or bias, but it was unclear whether similar measures were applied throughout the review.

The assessment of the methodological quality of included studies was poorly described and no results were reported. Appropriate meta-analytic methods were used, but the reported overall pooled estimates of diagnostic performance for dipstick tests did not address the stated objectives of assessing the effect of age on the diagnostic performance of dipsticks and comparing the performance of dipsticks with that of microscopy; data pertinent to these objectives were provided by only two studies and one study, respectively.

Therefore, the authors' conclusions should be viewed cautiously.

Implications of the review for practice and research

Practice: The authors stated that urine dipstick testing on a fresh sample can be recommended for diagnosing urinary tract infection in children over two years, but not for younger children.

Research: The authors stated that a new, good quality study, stratified by age and including a comparison between microscopy and urine dipstick testing against clinical diagnosis of symptomatic urinary tract infection is needed.

Funding

Not stated.

Bibliographic details

Mori R, Yonemoto N, Fitzgerald A, Tullus K, Verrier-Jones K, Lakhanpaul M. Diagnostic performance of urine dipstick testing in children with suspected UTI: a systematic review of relationship with age and comparison with microscopy. Acta Paediatrica 2010; 99(4): 581-584. [PubMed: 20055779]

Original Paper URL

http://onlinelibrary.wiley.com/doi/10.1111/j.1651-2227.2009.01644.x/abstract

Indexing Status

Subject indexing assigned by NLM

MeSH

Adolescent; Age Factors; Child; Child, Preschool; Humans; Infant; Reagent Strips; Urinalysis /methods; Urinary Tract Infections /urine; Young Adult

AccessionNumber

12010002394

Database entry date

22/12/2010

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.