Background: The Columbus Public Health (CPH) Laboratory is a CLIA certified lab that processes all specimens collected at the CPH Sexual Health Clinic. In April of 2015, the CPH Laboratory noticed discordant results of urethral Gram stain and Nucleic Acid Amplification Test (NAAT) for Neisseria gonorrhoeae (Ng) among males seen at the clinic. It is not unusual for the urethral Gram stains to be negative and a NAAT test to be positive, as the NAAT is more sensitive. However, CPH lab personnel noticed that there were several Ng positive urethral gram stains and Ng negative NAAT. As a result, the lab implemented several quality assurance (QA) measures to determine the cause of these discordant test results.
Methods: The CPH Laboratory implemented a variety of QA measures to assess if the discordant pairs were due to instrument error, collection error, laboratory technician error, specimen contamination, or environmental contamination. Several reliability and validity tests were conducted to evaluate these measures. A specimen and environmental contamination assessment was conducted with the facility director and the contracted cleaning company.
Results: A potential source of contamination was identified with the urine collection containers. All remaining urine collection containers were discarded and replaced. However, discordant results persisted. It was determined there were no errors in the collection or processing of the specimens. As a result of the QA the specimens were sent to the regional laboratory for additional testing. Test results indicated that the isolates were Neisseria meningitidis (Nm) and not Ng. CPH has subsequently classified this as an outbreak of Nm-associated urethritis among males.
Conclusions: In 2015, there were a total of 80 discordant isolates that have been sent for Nm confirmation testing and serogrouping. Testing results indicate the Nm strain was non-groupable. CPH continues to conduct surveillance and assess risk factors.