[False positive urine cultures in children under two years of age - own research]

The basis of the diagnosis of urinary tract infection in children is positive culture of properly collected urine sample. The reliability of the urine cultures depends on the method how the urine sample was taken and sometimes this may increase the risk of misdiagnosis.

To determine the frequency of false positive urine cultures taken from midstream to a container or to a plastic collection bag in children under 2 years of age.

The study included 50 children (25 girls, 25 boys) aged 12 days to 24 months (mean age 7.26±6.51months) referred to the hospital with suspicion of urinary tract infection. The most frequent indications for urine analysis were: history of infection and/or abnormalities of urinary tract in 28 (56%) children, failure to thrive in 8 (16%) and fever in 6 (12%). Urine was taken from midstream to a container in 32 (64%) children and collected to a plastic bag in 18 (36%) children.

Hospital verifications of urine cultures were performed by suprapubic puncture culture in 24 (48% children) or by catheterization of the urinary bladder in 26 (52%) children. Urinary tract infection was confirmed in 11 (34%) among 32 children who had positive culture of urine form midstream. None of the children with positive urine culture from a plastic collection bag had urinary tract infection confirmed by suprapubic puncture or catheterization.

Correct method of urine collection for bacteriological tests in children under two years of life can avoid the misdiagnosis of urinary tract infection and following unnecessary hospitalization, imaging procedures as well as potentially harmful treatment.