Performance of the APTIMA Combo 2 Assay for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Female Urine and Endocervical Swab Specimens

Abstract

The greater sensitivity of nucleic acid amplification tests (NAATs) for Chlamydia trachomatis and Neisseria gonorrhoeae permits the use of urine and other noninvasive specimens, which can increase the reach and decrease the costs of public health screening programs aimed at controlling these infections. This study evaluated the performance of the APTIMA Combo 2 assay, a multiplex assay based on the transcriptionmediated amplification reaction, for the simultaneous detection of both pathogens in endocervical swab and urine specimens from females. Combo 2 assay results were compared with patient infected status, which were available by using other commercial NAATs. Sensitivity and specificity for C. trachomatis were 94.2 and 97.6%, respectively, in swabs and 94.7 and 98.9%, respectively, in first-catch urine (FCU). Sensitivity and specificity for N. gonorrhoeae were 99.2 and 98.7%, respectively, in swabs and 91.3 and 99.3%, respectively, in FCU. The assay reliably detected both infections in coinfected patients. The Combo 2 assay can be recommended for use with endocervical swab and urine specimens from females, especially for screening tests for asymptomatic women in sexually transmitted disease surveillance programs. This Food and Drug Administration-cleared assay can be a useful tool in efforts to reduce the prevalence and incidence of C. trachomatis and N. gonorrhoeae infections in sexually active women and to prevent their costly and serious sequelae.

Nucleic Acid Amplification Testing for Neisseria gonorrhoeae

“…Thus, co-infections of N. gonorrhoeae and C. trachomatis may be missed by multiplex assays. Gaydos et al 27 found that of 56 known N. gonorrhoeae and C. trachomatis co-infections, six were missed by the Gen-Probe AC2 transcription-mediated amplification (TMA) assay, with C. trachomatis identified in two specimens only and N. gonorrhoeae identified in four specimens only. Competitive inhibition was also reported in the Roche Cobas Amplicor multiplex system.…”

“…By using TMA technology to amplify rRNA, the Gen-Probe AC2 assay has in theory the potential to detect lower concentrations of N. gonorrhoeae because the copies of 16S rRNA will usually exceed that of DNA targets used by other commercial N. gonorrhoeae NAATs. 27 Gaydos et al 27 found that the positive predictive values of the AC2 were 88.1 and 92.1% for swab and urine specimens, respectively. However, these figures were calculated using the Abbott LCx as the reference standard.…”

“…Such algorithms may also use an "infected patient" standard, whereby a patient's infectivity status is determined on the basis of results obtained from both urine and genital swab specimens. 27,56,75 Importantly, these expanded gold standards accommodate the increased sensitivity of NAAT tests while also providing statistical validity. However, these algorithms operate under the assumption that both gonococcal NAAT targets are unlikely to be present in commensal Neisseria strains occurring in these specimens.…”

Effect of Preanalytical Processing of ThinPrep Specimens on Detection of High-Risk Human Papillomavirus by the Aptima HPV Assay

“…For analysis by Aptima HPV on the Tigris DTS system, 1-ml ThinPrep aliquots were dispensed into tubes containing lysis medium. Paradigms of oligonucleotide-specific target capture, TMA, and hybridization protection (13) were utilized to generate a luminescencebased result. The assay detects E6/E7 mRNA from high-risk HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68.…”

Diagnosis of Chlamydia trachomatis Infection

“…Not only are these assays highly sensitive and specific, these can be easily implemented in a high throughput laboratory [133,[135][136][137][138].…”