[Urinary tract infection: a tailored diagnosis]

Abstract

Urine dipstick testing reveals the presence of esterase secreted by leukocytes, and nitrites produced by some bacteria. The presence of either one confirms the diagnosis of acute uncomplicated urinary tract infection, that is in a woman of childbearing age with typical symptoms. Indeed, false positive tests are rare in this population. In contrast, dipstick testing is much less reliable in aged patients, and those with incontinence or an urinary catheter. Because asymptomatic bacteriuria is frequent in this population which, on the other hand, suffers more often from urinary tract infections due to bacteria that don't produce nitrites, the specificity and sensitivity of dipstick testing are low and should motivate a comprehensive approach to avoid unnecessary treatments or missed diagnoses.