Semiautomation of Nucleic Acid-based Assays for Chlamydia trachomatis and Neisseria gonorrhoeae

Abstract

The US prevalence rates of sexually transmitted diseases associated with Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) are as high as 27% (1) and 56% (2), respectively. Routine screening for both conditions is recommended for several risk groups, and infections with CT and GC frequently coexist (3). Because both infections are often asymptomatic, screening is important in efforts to slow the spread of infection. Recent studies compared amplified with nonamplified testing (4)(5)(6)(7)(8)(9)(10) and swab with urine specimens (4)(8)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Because recommendations vary (21)(22)(23)(24)(25), each laboratory must decide which test(s) to use by considering the prevalence of infection, assay sensitivity and specificity, cost-effectiveness, laboratory work flow, and types of specimens received. Several tests may be required to best serve customers with different needs. We developed a menu of semiautomated tests, including amplified CT, nonamplified CT, and nonamplified GC assays. We describe two novel menu choices here: (a) a combination of the nonamplified PACE® 2 GC assay (Gen-Probe, Inc.) with the AMPLIFIEDTM Chlamydia Trachomatis Assay (AMP CT; Gen-Probe, Inc.) for swab specimens; and (b) AMP CT for urine specimens. We used the TECAN GENESIS RSP instrument (1.426 m × 0.780 m × 1.200 m; TECAN US, Inc.). It has an eight-tip arm and uses 1-mL, extended length, disposable, filter pipette tips with level-sensing capability. We designed and machined custom deck plates to support the necessary specimen racks, assay racks, and reagent reservoirs. With approval from the Institutional Review Board, four clinical sites collected urogenital swab specimens using the standard PACE 2 specimen collection method, and two clinical sites collected …