Cervical chlamydial infections: diagnostic accuracy of the Papanicolaou smear

To assess the reliability and accuracy of the Papanicolaou smear for the detection of cervical Chlamydia trachomatis infections, we obtained chlamydial cultures and cervical smears from 252 patients attending a gynecologic service during an eight-month time period. In 12 of these patients (4.8%), the cervical culture was positive for chlamydiae but the cytologic smear was negative for chlamydial inclusions. Five smears (2.2%) were cytologically positive for chlamydiae but were negative by culture. In none of the patients were both culture and smear positive for chlamydiae. In our experience the smear was a completely unreliable test for the diagnosis of cervical C trachomatis infections. The cytologic smear should not replace culture for the detection of chlamydial infections.