EVALUATION OF URINE-BASED SCREENING STRATEGIES TO DETECT CHLAMYDIA-TRACHOMATIS AMONG SEXUALLY ACTIVE ASYMPTOMATIC YOUNG MALES

Objective.-To evaluate the performances of diagnostic screening tests alone or in combination to detect asymptomatic chlamydial urethral inf ection in young males. Design.-Comparisons of the performance profiles of the following chlamydia screening strategies were done: urethral c ulture; identification of polymorphonucleocytes (PMNs) on spun first-v oid urine (FVU); urinary leukocyte esterase test (LET) on unspun FVU; chlamydial enzyme immunoassay (EIA) applied to FVU sediment; combining LET on unspun FVU followed by EIA with or without direct fluorescent antibody (DFA) confirmation on FVU sediment; and combining PMNs on spu n FVU followed by EIA with or without DFA confirmation. Setting.-Gener al clinics at a youth detention center, university-based teen clinic, college health service, and a military screening clinic. Patients.-A t otal of 618 males aged 12 to 35 years (mean, 17 years) were recruited as a convenience sample; site participation rates ranged from 50% to 8 0%. Eligible subjects were sexually active, denied symptoms of urethri tis, and had taken no antibiotics in the prior 2 weeks. Main Outcome M easures.-Sensitivity, specificity, and positive and negative predictiv e values of each test strategy's ability to detect Chlamydia trachomat is infection, and cost to confirm each positive case. Results.-With a 7% prevalence of chlamydial infection, tissue culture had a sensitivit y of only 61%. However, two strategies yielded significantly better pe rformance profiles compared with the others: EIA confirmed by DFA test with a sensitivity of 84%, a specificity of 100%, and a cost to ident ify each positive case of $434; and PMNs followed by EIA confirmed by DFA test with a sensitivity of 78%, a specificity of 100%, and a cost to identify each positive case of $199. The LET followed by EIA-DFA ha d a similar performance profile to the PMN test strategies. Conclusion s.-A combination of a nonspecific screening of FVU for PMNs or LET fol lowed by specific testing with EIA with DFA confirmation has superior clinical and cost-effective performance for detecting asymptomatic C t rachomatis urethritis in young males compared with other strategies. H owever, an evaluation of the medical, fiscal, and psychological benefi ts and risks associated with a specific screening strategy for sexuall y transmitted diseases must be made before adopting a specific strateg y for a particular population.