Is seminal fluid a suitable specimen for detecting chlamydial infection in men?

As genital chlamydia infection is considered the most prevalent sexually transmitted bacterial disease worldwide, its correct diagnosis has a great clinical and epidemiological importance. Urethra is the recommended site for collecting specimen for detection of Chlamydia trachomatis in men, but urethral swabbing is very inconvenient for the patients. Testing of seminal fluid has two advantages: taking the sample is more convenient for the patient, and the ejaculate would provide more information on the possible infection of the upper genital tract. Three non-culture methods-enzyme immunoassay (EIA), DNA hybridization, and polymerase chain reaction (PCR)-were used for evaluation of suitability of seminal fluid as a sample for detection of Chlamydia in 4 patient groups comprising 259 symptomatic and asymptomatic, urology and andrology patients. The seminal fluids were tested parallel with the urethral samples. In one group of patients with typical prostatic complaints expressed prostatic secretion was examined parallel with urethral swab. C. trachomatis positivity rates were much higher in symptomatic (49.1%) than in asymptomatic patients (12.3%) in all kinds of sample. Seminal fluid was somewhat more frequently positive (7.9%) than urethral sample (6.2%). Simultaneous positivity was relatively rare (3.3%), it occurred most frequently in samples of patients with possible accessory gland infection tested by EIA. In a group of 17 patients with typical prostatic complaints the expressed prostatic secretion alone was positive in 7 cases, whereas only other two of the parallel urethral samples proved positive by PCR, simultaneous positivity occurred in one case. These findings suggest that testing of the ejaculate and/or the prostatic secretion parallel with the urethral sample would improve the sensitivity of detection of chlamydial infections.