Study objective: To examine whether clinical or laboratory findings could distinguish Chlamydia trachomatis (CT) from urinary tract infection (UTI) among adolescent females in whom providers tested for both.
Design, setting, participants: A laboratory database at an urban teen health center was reviewed to identify females who had both urine culture and ligase chain reaction (LCR) test for CT ordered at the same visit. History and physical findings were abstracted from the medical record. There were 81 visits with retrievable laboratory results and chart documentation.
Main outcome measures: UTI was defined as >1000 colony-forming units on culture, and CT was defined as positive LCR test. Pearson's Chi-squared test was used to assess strength of the hypothesized associations.
Results: UTI was diagnosed in 20 (24%) and CT in 18 (22%) of 82 visits. Concurrent CT was diagnosed in 6 of 20 subjects with UTI. Symptoms and physical signs did not differentiate UTI from CT. Positive urinary nitrites were associated with UTI, but did not exclude CT. Similarly, wet prep evidence of trichomonas or white blood cells was associated with CT, but did not exclude UTI. Clinical diagnosis of CT or UTI was 50% sensitive and 70% specific.
Conclusions: Adolescent females who are screened for both CT and UTI have high rates of concurrent disease. Urinary or vaginal symptoms do not differentiate well between these infections. Clinical diagnosis is imprecise, suggesting that adolescent females with vaginal or urinary symptoms should be tested for both CT and UTI.