[The validation of a rapid diagnostic method for urinary infection in the school-age population]

Validity of visual reading of a reactive strip is measured, in comparison with automatized reading and the exam of the urinary sediment, in 562 school pupils with ages between 6 and 16 years. Using urine culture as standard reference, sensibility of the leukocyte-esterase (L-E) test, nitrites and red cells was 66.7%, 33.3% and 66.7% respectively, for the visual reading; 66.7%, 33.3% and 33.3% for automatized reading, respectively; and 66.7% for leukocyturia, and 33.3% for hematuria in the urine sediment. Specificity of tests was 84.9%, 99% and 42.7% for L-E, nitrites and red cells, in visual reading; 92.5%, 100% and 80.8% for the same tests in automatized reading, and 94.5% (leukocyturia) and 86.3% (red cells) in the urinary sediment. Validity of these diagnostic methods results different depending on the population they are applied to. Even though the multi-urine test is still the most effective test in a symptomatic population and the less expensive, it would be not recommendable its use as a screening test in a school population with hidden urinary infection.