Tests for Chlamydia trachomatis and Neisseria gonorrhoeae, which can provide results rapidly to guide therapeutic decision-making, offer patient care advantages over laboratory-based tests that require several days to provide results. We compared results from the Cepheid GeneXpert CT/NG (Xpert) assay to results from two currently approved nucleic acid amplification assays in 1,722 female and 1,387 male volunteers. Results for chlamydia in females demonstrated sensitivities for endocervical, vaginal, and urine samples of 97.4%, 98.7%, and 97.6%, respectively, and for urine samples from males, a sensitivity of 97.5%, with all specificity estimates being >99.4%. Results for gonorrhea in females demonstrated sensitivities for endocervical, vaginal, and urine samples of 100.0%, 100.0%, and 95.6%, respectively, and for urine samples from males, a sensitivity of 98.0%, with all estimates of specificity being >99.8%. These results indicate that this short-turnaround-time test can be used to accurately test patients and to possibly do so at the site of care, thus potentially improving chlamydia and gonorrhea control efforts. Chlamydia trachomatis and Neisseria gonorrhoeae are the agents of the two most prevalent bacterial sexually transmitted infections (STIs) reported to the Centers for Disease Control and Prevention (CDC), accounting for Ͼ1.6 million reported infections in the United States in 2010 (1). The CDC estimates that STIs cost the health care system $1.5 billion annually. Since these infections, especially chlamydia, are most often asymptomatic, the CDC recommends yearly screening for chlamydia in all sexually active women aged 16 to 25 years. Further, since coinfections are common, most diagnostic test platforms assay for both organisms. Nucleic acid amplification tests (NAATs) are now recommended by the CDC (2) as the tests of choice; however, current NAATs are classified as being of high or moderate complexity and might take 1 to 2 days for results to become available. New assays and new platforms that provide results at the time of patient visits are urgently needed, since many patients do not return for their results when laboratory-based tests that require several days for their results are performed (3, 4).The Cepheid GeneXpert CT/NG (Xpert) assay is a rapid (Ͻ2 h to results) NAAT assay that can be performed in on-site laboratories. The assay detects the DNA of C. trachomatis and N. gonorrhoeae from endocervical, vaginal, and urine specimens of females, as well as from urine specimens of males, from both symptomatic and asymptomatic individuals. The Xpert test is performed using a modular cartridge-based platform for testing each specimen by nucleic acid amplification, and it can process from 1 to 96 specimens in Ͻ2 h with easy-to-use cartridges that minimize processing steps and contamination. This study compares the clinical performance (as measured by sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV]) of the Xpert assay to the patient infection status (PIS)...

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The Aptima Combo 2 (AC2) and Aptima CT (ACT) (Hologic Inc., San Diego, CA) are nucleic acid amplification tests (NAATs) that detect Chlamydia trachomatis. AC2 also detects Neisseria gonorrhoeae. Storage and temperature conditions may impact the utility of NAATs in some settings and screening programs. We evaluated specimen stability for use beyond the Aptima package insert specifications for temperature and duration of storage (between 2°C and 30°C and 60 days, respectively) in two studies: (i) dry C. trachomatis-seeded swabs were used with ACT after storage at 4°C, 23°C, or 36°C for up to 84 days and (ii) swabs seeded with C. trachomatis and N. gonorrhoeae and then placed in transport medium were tested with AC2, after being mailed via the U.S. Postal Service to three different sites. Prolonged storage of samples had no effect, and samples stored at 4°C, 23°C, and 36°C for up to 84 days yielded comparable ACT positivities, although there was a drop in signal intensity for virtually all specimens under all storage/shipping conditions after day 21. In the mailing study, 80%, 52% and 29% of seeded swabs were exposed to temperatures of Ͼ30°C during three rounds in transit, and 2% reached temperatures of Ͼ40°C. No evidence of signal degradation in the AC2 assay for detection of C. trachomatis or N. gonorrhoeae was observed, although some mailed swabs took more than 5 weeks to reach the laboratory site. These two studies support the potential use of swabs at temperatures above 36°C and storage beyond 60 days and provide confidence regarding this commercially available NAAT for testing of specimens after mailing.KEYWORDS Chlamydia trachomatis, Neisseria gonorrhoeae, detection, nucleic acid amplification test, stability, swabs N ucleic acid amplification tests (NAATs) are highly sensitive and specific for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae (1-3). These tests are now widely available and used routinely for diagnosis and screening of men and women for genital tract infections (4). Each NAAT has package insert (PI) instructions that detail the requirements for specimen type and handling. However, off-label use of these NAATs is permissible if the laboratory performs validation studies demonstrating results comparable to those of standard tests. For example, NAATs are not currently FDA cleared for use as tests for pharyngeal and rectal C. trachomatis or N. gonorrhoeae, but numerous laboratories have evaluated these specimens, verifying their suitability for testing (5).The Aptima Combo 2 (AC2; Hologic Inc., San Diego, CA) is a NAAT that detects both C. trachomatis and N. gonorrhoeae using a single specimen (6). The PI specifies that

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