Screening for urinary tract infections in a gynaecological setting: validity and cost-effectiveness of reagent strips

This study aims to test the validity and cost-effectiveness of reagent-strip analysis compared with microbiological laboratory testing for mass screening of urine for urinary tract infections in a gynaecological setting. Over a six-month period, urine samples from a convenient group of 228 women presenting in a gynaecological ward of an NHS Trust hospital were tested using Ames 8SG reagent strips to detect leucocyte esterase and nitrite. Total bacterial counts were also carried out; urine culture was recorded as positive if there was > 10(5) organisms/mL. Validity of the dipstick tests was measured, using four criteria (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV]), against the results of laboratory analysis. The combined use of the leucocyte esterase and nitrite tests produced results as follows: sensitivity, 96.4%; specificity, 88.5%; PPV, 54%; and NPV, 99.4%. Cost-effectiveness for visible costs was calculated as 48.6% for the 12.3% rate of infection in this study. The use of reagent strips in a mass-screening programme in a gynaecological setting proved both valid and cost-effective.