title: Stability Studies on Dry Swabs and Wet Mailed Swabs for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Aptima Assays.
abstract: The Aptima Combo 2 (AC2) and Aptima CT (ACT) (Hologic Inc., San Diego, CA) are nucleic acid amplification tests (NAATs) that detectChlamydia trachomatisAC2 also detectsNeisseria gonorrhoeaeStorage 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) dryC. 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 withC. trachomatisandN. gonorrhoeaeand 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 >30°C during three rounds in transit, and 2% reached temperatures of >40°C. No evidence of signal degradation in the AC2 assay for detection ofC. trachomatisorN. gonorrhoeaewas 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.
authors.affiliation: Department of Laboratory Medicine, University of California, San Francisco, California, USA Jeanne.moncada@ucsf.edu.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Moncada
authors.affiliation: Division of Infectious Diseases, University of Alabama, Birmingham, Alabama, USA.
authors.forename: Carey B
authors.initials: CB
authors.lastname: Clark
authors.affiliation: Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Holden
authors.affiliation: Division of Infectious Diseases, University of Alabama, Birmingham, Alabama, USA.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Hook
authors.affiliation: Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Charlotte A
authors.initials: CA
authors.lastname: Gaydos
authors.affiliation: Department of Laboratory Medicine, University of California, San Francisco, California, USA.
authors.forename: Julius
authors.initials: J
authors.lastname: Schachter
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D002690:Chlamydia Infections / Q000175:diagnosis*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D006069:Gonorrhea / Q000175:diagnosis*; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification*; D013048:Specimen Handling / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D014481:United States
keywords: Chlamydia trachomatis; Neisseria gonorrhoeae; detection; nucleic acid amplification test; stability; swabs