SummaryScreening tests for bacteriuria based on two different principles were evaluated in 1582 schoolgirls aged 5-11 years, and in 26 girls aged 3-16 years attending hospital with symptomatic urinary tract infection. Tests for hypoglucosuria, performed by a semi-automated fluorometric method and with Uriglox strips on early-morning urine samples voided after overnight fasting, gave unacceptably high false-negative rates (16.70o and 20.8°O respectively).Oxoid and Uricult dipslides were immersed in fresh midstream specimens of urine obtained at school and read after overnight incubation at 37 C. Both gave comparable results, with low false-positive rates and no false-negative responses. The higher cost of screening by dipslides was halved by using the "dipstream" technique, which also gave no false-negative results. Its falsepositive rate of 13.5"O could be reduced to 1.8"(, by disregarding colony counts of 108 non-faecal organisms and over per litre, which appear unimportant in schoolchildren.Bacteriuria was found in 2.3%) of the schoolgirls; 39( of them had symptoms, compared with 7.2U, of the healthy girls, and 25) showed vesicoureteric reflux, which in 17") was associated with renal scarring. Since the natural history of covert bacteriuria and its relationChildren's Hospital, Birmingham B16 8ET