Detection of Chlamydia trachomatis and Neisseria gonorrhoeae Infections in North American Women by Testing SurePath Liquid-Based Pap Specimens in APTIMA Assays

Abstract

The APTIMA COMBO 2 assay, which detects and amplifies rRNA from Chlamydia trachomatis and/or Neisseria gonorrhoeae, is approved for use on ThinPrep liquid-based Pap test specimens. The objective was to determine the clinical utility of the APTIMA assays (APTIMA COMBO 2 assay, APTIMA CT assay for Chlamydia trachomatis, and APTIMA GC assay for Neisseria gonorrhoeae) for screening women during their annual Pap exam, using SurePath liquid-based Pap test specimens. Two cervical samples were collected from 1,615 females attending six clinical sites in North America. A cervical broom sample was processed for cytology, with the residuum aliquoted into an APTIMA specimen transfer kit tube. The second cervical swab sample was put into APTIMA specimen transport medium, and both samples were tested with each APTIMA assay on a direct sampling system. Using a subject-infected status that utilized cervical-swab specimen results from two APTIMA assays, the prevalence was 7.9% for Chlamydia trachomatis and 2.5% for N. gonorrhoeae. Annual screening for cervical abnormalities using a Pap test has resulted in a substantial reduction in morbidity and mortality from cervical cancer (11). There are three liquidbased Pap tests (LPTs) approved by the United States Food and Drug Administration (FDA): PreservCyt ThinPrep (Cytyc, Boxborough, MA), SurePath (TriPath Care Technologies, Burlington, NC), and Cytotek MonoPrep (Monogen, Inc., Vernon Hills, IL). Liquid-based cytology has provided greater Pap testing accuracy, and the sample may serve as a specimen to test for infectious agents, such as human papillomavirus (2, 11), Chlamydia trachomatis (5, 14), and Neisseria gonorrhoeae (6, 9). The APTIMA COMBO 2 assay, APTIMA CT assay for Chlamydia trachomatis, and AP-TIMA GC assay for Neisseria gonorrhoeae are transcriptionmediated amplification tests that utilize target capture specimen processing for the in vitro qualitative detection of rRNA from C. trachomatis and/or N. gonorrhoeae. The assays are approved for use on cervical swab (CS) samples, vaginal swab samples, urethral swab samples, and first-catch urine samples. The APTIMA COMBO 2 assay is approved for use with ThinPrep LPT specimens. A limited number of studies have been published using both amplified and nonamplified tests for C. trachomatis or N. gonorrhoeae in liquid-based specimens and have concentrated on the use of ThinPrep samples (1, 5-10; D. Fuller, T. Davis, and J. Talbott, unpublished data). Our objective was to determine the clinical utility of the APTIMA assays (Gen-Probe Incorporated) for screening women for C. trachomatis and N. gonorrhoeae during their annual Pap examination by using SurePath LPT specimens. MATERIALS AND METHODSA total of 1,615 female subjects signed consent forms while being enrolled during 2004 at six clinical sites in North America: University of North Carolina (UNC), Chapel Hill, NC; University of Alabama (UAB), Birmingham, AL; St. Joseph's Healthcare (SJH), Hamilton, ON, Canada; University of OklahomaTulsa (UOT), Tulsa, OK; University of Illinoi...

Cost-effectiveness Analysis of Chlamydia trachomatis Screening Via Internet-based Self-collected Swabs Compared With Clinic-based Sample Collection

“…Seven of these studies met our full inclusion and exclusion criteria: original study on Chlamydia screening among women; and vaginal swab or endocervical swab used for AC2 testing. 15-21 …”

Comparison of Three Assays for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in SurePath Pap Samples and the Role of Pre- and Postcytology Testing

“…Previous studies have shown that differences in analytical sensitivity of nucleic acid amplification tests (6) and inhibitors of DNA amplification (2, 3) may account for lower sensitivities in the AMP and PT assays. The sensitivity of AC2 for C. trachomatis in SurePath L-Pap samples in the present study was equal to that for testing of a CS (97.1%) and higher than those observed previously in a multicenter study (5) and two validation studies (4, 7) (Table 1).…”

Low Rates of Both Asymptomatic Chlamydia Screening and Diagnostic Testing of Women in U.S. Outpatient Clinics

“…A chlamydia test may be easily performed during a pelvic examination by obtaining a swab specimen of the endocervix or vagina, or by using the residual liquid from a liquid-based cytology specimen obtained during cervical cancer screening. 5,16 If a pelvic examination is not performed, then a chlamydia test can be done using a self-collected vaginal swab or a urine specimen. 5,17 However, these opportunities were missed at most visits to outpatient clinics.…”

“…1 More than one half of these reported cases were in women aged [15][16][17][18][19][20][21][22][23][24][25] years. Yet this rate likely underestimates the true burden of chlamydia, because of insufficient screening and reporting.…”