Assay Integrity of a PCR Influenza Point-of-Care Test Remains Following Artificial System Contamination

Background: Healthcare providers who have access to tests at the point of care (POC) are increasingly requesting the same performance from the POC test as they expect from the laboratory. With the introduction of the cobas^® Liat instrument, highly sensitive molecular diagnostic testing can be performed closer to the patient in CLIA-waived, POC settings. As more sensitive tests become available, there is concern regarding contamination of instrumentation owing to improper handling, mistakes made when processing, or environmental contamination. Recent concerns were raised when a nurse performed environmental surveillance for flu A/B by inserting a dry swab into the cobas Liat instrument and then ran it as a sample on the instrument, generating a positive result. This finding stimulated questions about the possibility of system contamination contributing to false-positive results, ultimately leading to the possibility of providing incorrect treatment to patients.

Methods: To assess the likelihood of system contamination contributing to the generation of false-positive results, in this study we contaminated a cobas Liat System with flu A/B-positive control material. The system contamination was then assessed by swabbing exposed surfaces. Following confirmed system contamination, negative control samples were processed to determine whether system contamination had an impact on the expected negative results.

Results: Instrument contamination was confirmed, and no detectable flu A/B signal was observed for any of the negative control tubes run immediately following confirmation of system contamination.

Conclusion: Environmental contamination of the Liat instrument does not have an impact on the integrity of the result.