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Factors that influence confirmation of Neisseria gonorrhoeae positivity by molecular methods

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Original languageEnglish
JournalJournal of Clinical Microbiology
Early online date24 May 2019
Publication statusE-pub ahead of print - 24 May 2019


Several Neisseria gonorrhoeae (NG) nucleic acid amplification tests (NAATs) exist with high sensitivity. However, specificity of NG NAAT testing may be suboptimal, particularly in extra-genital biospecimens. Consequently, confirmation with a second NAAT is common, although represents a burden on resources. Furthermore, the rationale for confirmation is contentious.The objective of this work was to assess NG confirmation in over 13,000 NG screen-positive samples representing various biospecimens and three separate screening assays: the Abbott Real Abbott RealTime CT/NG (Abbott Molecular Inc., Des Plaines, IL), the Cobas CT/NG test (Roche Diagnostics, Indianapolis, IN) and the BD ProbeTec ET CT/GC Amplified DNA assay (Becton Dickinson and Company, Sparks, MD). Factors predictive of confirmation were determined via logistic regression involving: sex, year, whether the samples was formally validated and sample site.Level of confirmation varied according to screening assay (96.2%, 86.0% and 73.9%) for the Abbott, Roche and BD test respectively in sample types formally included according to manufacturers instructions (i.e.-validated). Sex did not affect confirmation for 2/3 assays and the likelihood of confirmation of samples not formally included in manufacturer instructions (ie non validated) was 89.1%, 82.1% and 59.2% for the Abbott Roche and BD test respectively. Rectal swabs, which are non validated samples, confirmed in 91.5%, 90.1% and 87.4% of samples initially tested with the respective assaysThe requirement to confirm NG in validated samples is not required for all NAATs although initial, assay-specific evaluation is justified given observed variability. Rectal samples represent robust biospecimens for NG NAAT testing and do not require confirmation when screened with the assays described.

ID: 86352702