Comparison of Performances of Two Commercially Available Tests, a PCR Assay and a Ligase Chain Reaction Test, in Detection of Urogenital Chlamydia trachomatis Infection

Abstract

The diagnostic performance of a PCR test (Roche Cobas Amplicor CT/NG Test) and that of a ligase chain reaction (LCR) test (Abbott LCxChlamydia trachomatis assay) were compared by using endocervical and urethral swab specimen culture as a reference test. First-void urine (FVU) and endocervical and urethral swab specimens were collected from 1,015 unselected patients attending a sexually transmitted disease clinic and a clinic for adolescents in Helsinki, Finland. Chlamydia trachomatis was cultured from samples from the endocervix or urethra. PCR was performed with fresh and frozen urine and the culture transport medium. LCR was performed with fresh and frozen urine and LCx swab transport medium. Diagnostic consistency and diagnostic accuracy were statistically tested. The test results were identical for 984 patients (97%). Discrepant results were observed for 31 patients. Overall, LCR and PCR showed excellent kappa coefficients of consistency for both swab and FVU specimens (0.93 and 0.95, respectively). Sixty-one patients (6%) were culture positive. Testing of FVU by LCR or PCR increased the overall positivity rates to 7.0 and 7.7%, respectively. While PCR of FVU detected the greatest number of C. trachomatis infections (sensitivity, 96.1%), for some PCR-positive FVU specimens the results could not be confirmed (specificity, 99.6%). PCR and LCR were more sensitive than culture (sensitivities, 92 and 93% versus 79% for culture) in the diagnosis of genital C. trachomatis infection. In conclusion, both tests can be recommended for use in the clinical laboratory and for the screening of asymptomatic C. trachomatis infections.

Prevalence and distribution of Chlamydia trachomatis genovars in Indian infertile patients: a pilot study

“…This suggests that young women are the most at risk for Chlamydia and confirms that these individuals are an important target for health education interventions to encourage behavioural changes. Previous studies have shown that diagnosing C. trachomatis infections in women is difficult since, most infections are asymptomatic (13,14). However, in the present study, vaginal discharge, lower abdominal pain, irregular menstruations were significantly associated with C. trachomatis infection in infertile women.…”

Evaluating Adolescents in Juvenile Detention Facilities for Urogenital Chlamydial Infection

“…Although the diagnosis of chlamydial infection is often made by LCR, urine LCR and cervical LCR are not perfect tests, so we derived their test characteristics from a review of the literature (Table 1). [7][8][9][10][11][12][13] The sensitivity and specificity of urine LE testing in males were derived from the cohort. 5 There were 308 urine specimens evaluated by LE testing in males; 71 (23%) were positive for Chlamydia, of which 21 cases were confirmed by urine LCR.…”

Case finding and case management of chlamydia and gonorrhea infections among women: What we do and do not know

“…In contrast, the prevalence of chlamydia seems to vary widely across and within regions-from below 5 percent to around 25 percent in all regions. have emerged as the standard tests for chlamydia, with sensitivity and specificity better than those from culture (Buimer et al 1996;Gray and Wawer 1996;Puolakkainen et al 1998;Stary et al 1997).…”