INTRODUCTION: A routine follow-up urine sample (FUS) in the form of a midstream urine sample (MSU) is recommended after treatment for urinary tract infection (UTI) according to the Danish Paediatric Society (DPS) and "Lægehåndbogen" published by Danish Regions. We studied the effect of FUS with a focus on patients without symptoms at the time of FUS.

METHODS: Consecutive patients below 16.0 years treated for upper or lower UTI from 1 January 2009 to 31 December 2009 at Hvidovre Hospital in accordance with the guidelines of the department and the DPS. All patients were asked to provide a FUS within 21 days.

RESULTS: A total of 87 patients were treated for upper UTI: 59 girls and 28 boys, the median age was 1.1 year (range: 0.1-15.6 years); and 42 girls were treated for lower UTI, their median age was 8.2 years (range: 2.5-15.3 years). After treatment, the risk of a UTI was 0% (0/87) after upper UTI versus 19% (8/42) after lower UTI (Fisher's exact test (FE), p < 0.0001). Among those without symptoms at FUS, the risk of a UTI was 0% (0/75) (95% confidence interval (CI): 0-4.9%) after upper UTI versus 4% (1/26) (95% CI: 0.1-19.6%) after lower UTI (FE, p = 0.2754). The cost of requesting a FUS in patients without symptoms was 166 euro after treatment for upper UTI and 66 euro after treatment of lower UTI.

CONCLUSION: We do not recommend a FUS after treatment for UTI as the 95% CI of risk of missing UTI after treatment for upper UTI was below 5%. This strategy will save the patients/families and the health-care system. However, if a child has symptoms after treatment for UTI, it must be examined.

FUNDING: not relevant.

TRIAL REGISTRATION: The study was approved by the Danish Data Protection Agency (J. no. 2007-58-0015).