Screening for urethral infection in adolescent and young adult males.

We evaluated the urinary leukocyte esterase (LE) dipstick as a predictor of a positive urethral culture for Neisseria gonorrhoeae and/or Chlamydia trachomatis in adolescent and young adult males. Sexual and sexually transmitted disease (STD) histories were also analyzed to determine predictors of infection. Subjects were recruited from sexually active males attending an adolescent medicine clinic. Patients were interviewed regarding presence of symptoms of urethritis and a variety of clinical variables. First-voided urine for LE dipstick and urethral swabs for gonorrhea and C. trachomatis cultures were obtained. One hundred patients (mean age, 19.2 years) were asymptomatic; 50 patients (mean age, 19.0 years) had symptoms of urethritis. In asymptomatic patients, the sensitivity, specificity, predictive value positive (PVP), and predictive value negative (PVN) of the LE dipstick were 0.31, 0.92, 0.57, and 0.90, respectively. These values were 0.66, 0.71, 0.76, and 0.60, respectively, in symptomatic patients. In each patient group the dipstick was more sensitive in detecting, and a better predictor of, a positive culture for gonorrhea than Chlamydia. LE dipstick results and clinical variables were evaluated as correlates of infection using stepwise logistic regression. A positive LE dipstick and four additional variables increased the probability of obtaining a positive culture for one or both organisms from symptomatic patients. These variables were the following: sexual contact in the previous month with a partner diagnosed as having a sexually transmitted disease, having ever used a condom, five or more lifetime sexual partners, and more than one sexual partner in the past month. Only a positive LE dipstick entered the model as a predictor of infection in asymptomatic patients.(ABSTRACT TRUNCATED AT 250 WORDS)