Diagnosis of Chlamydia trachomatis urethritis in men by polymerase chain reaction assay of first-catch urine

Abstract

To determine the accuracy of a recently developed polymerase chain reaction (PCR) urine assay to detect Chiamydia trachomatis urethral infection in men, we obtained urethral swabs and first-catch urine from 365 men attending a sexually transmitted diseases clinic. Thirty-three (91%Y) of the 365 men were infected with C. trachomatis as defined by urethral culture. Thirty-two of the 33 men with culture-positive urethral swabs also had PCR-positive urine assays. Of 332 patients with culture-negative urethral swabs, 325 had PCR-negative urine. Compared with chlamydia culture of urethral specimens, PCR assay of urine samples thus had a sensitivity of 97% and a specificity of 98%. The positive predictive value of the urine PCR assay was 82%, and the negative predictive value was 99%. Analysis of discrepant results indicated that six of seven PCR-positive, urethral culture-negative patients probably had chlamydial urethritis. All six patients had symptoms of urethritis and had either a positive urethral swab PCR or a positive urine PCR with a different amplification target. After resolution of discrepant results, (defining true positives as the 33 culture-positive patients and the 6 PCR-positive, culture-negative patients just described), the sensitivity and specificity of culture were 85% (33 of 39) and 1O0o (326 of 326), respectively. The revised sensitivity and specificity of PCR were 97% (38 of 39) and 99.7% (325 of 326), respectively. We conclude that this urine PCR assay provides a highly sensitive, noninvasive alternative method for the detection of C. trachomatis urethral infection in high-risk men attending a sexually transmitted diseases clinic. This assay could greatly facilitate the testing of larger numbers of male patients for chlamydial infection and should be studied in other settings.

Polymerase chain reaction assay with urine specimens in the diagnosis of acute Chlamydia trachomatis infection in women

“…7,8 The presence of DNA polymerase inhibitors was first described in endocervical specimens, where the ensuing percentage of false negative results varied between 4% and 10% in different reports, depending on the prevalence of chlamydial infection in the population studied. 4,5 PCR inhibitors were also found in male urine although they were first thought to occur less frequently than in endocervical specimens, i.e., in 0-3% of true positive specimens. 3,4 Wiesenfeld et al 14 reported the presence of PCR inhibitors in almost 10% of positive male urine specimens in a high-risk population with 17% incidence of chlamydial infection.…”

“…PCR on male urine specimens has been shown to be a highly sensitive and specific non-invasive technique for the diagnosis of C. trachomatis, providing an opportunity for the identification of both asymptomatic and symptomatic infected patients. 3,4 According to recent studies, the amplification power of PCR appears to make possible the same approach in females as well. 7,8 The presence of DNA polymerase inhibitors was first described in endocervical specimens, where the ensuing percentage of false negative results varied between 4% and 10% in different reports, depending on the prevalence of chlamydial infection in the population studied.…”

“…The sensitivity of PACE 2 assay has been comparable to that of cell culture (96.7-100%), 1,2 and the Amplicor PCR has been shown to be even more sensitive than culture. [3][4][5] In a recent study, we demonstrated an equal sensitivity (90% vs. 88%) between Amplicor PCR and PACE 2 performed on cervical swab specimens obtained from a high-risk population. 6 Studies on the use of PCR with male urine specimens have demonstrated an enhanced sensitivity compared to that achieved by conventional chlamydial cell culture with urethral swab specimens.…”

“…6 Studies on the use of PCR with male urine specimens have demonstrated an enhanced sensitivity compared to that achieved by conventional chlamydial cell culture with urethral swab specimens. 3,4 Recently, PCR with urine specimens has been applied for the diagnosis of C. trachomatis infection in women. 7,8 These studies have suggested urine as a superior sample material for the detection of C. trachomatis also in women, and this finding has been explained by the fact that a proportion of female C. trachomatis infections can only be detected in the urethra.…”

New methods in diagnostic and epidemiological research of Chlamydia trachomatis infections: the tide is turning molecular

“…In most studies using either cervical swabs, urethral swabs from females or males, or urine specimens from males, the Amplieor PCR assay was more sensitive than the reference methods used, such as the cell culture method, the Chlamydiazyme assay or the Gen-Probe PACE 2 assay [36,[38][39][40][41][42][43][44][45][46]. In one study using cervical spec-imens, the observed sensitivity of the Amplieor PCR assay was lower than that of the cell culture method [47].…”