15th March 2021 Product update: rapidvirology staff writer
FDA Alert COVID-19 Testing Labs to False-Positives with Multiplex Assay
The U.S. Food and Drug Administration (FDA) is alerting clinical laboratory staff, point-of-care (POC) facility staff, and health care providers that false positive results can occur with the Roche Molecular Systems, Inc. (Roche) cobas SARS-CoV-2 & Influenza A/B Nucleic Acid Test for use on the cobas Liat System.
The false-positive results may be related to two issues observed by Roche:
- Roche identified that the assay tubes may sporadically leak, causing an obstructed optical path in the Liat analyzer, producing abnormal PCR growth curves. This could lead to invalid or erroneous positive results, particularly for the Flu B test. If a tube leak occurs, later testing runs may have an increased likelihood of false positive Flu B results.
- Roche determined that abnormal PCR cycling in the reaction tubes may also produce abnormal PCR growth curves, leading to erroneous results. The issue is sporadic and may be caused by multiple factors happening at the same time, such as hardware positioning, volume movement, and curve interpretation. This issue may cause false positive results for multiple analytes (Influenza A, Influenza B and/or SARS-CoV-2) in a single testing run.
False-positive results could lead to improper patient management. False-positive results may also lead to unnecessary isolation and additional health monitoring, delayed diagnosis and treatment, and misallocation of resources used for surveillance and prevention for other infections or health conditions.
The FDA recommends users of the cobas SARS-CoV-2 & Influenza A/B Nucleic Acid Test for use on the cobas Liat System:
- Monitor for unexpected clusters of positive Flu B results, as this may indicate the cobas Liat System has experienced a tube leak.
- Repeat tests when two or three analytes are positive. Different results on the repeat test may indicate abnormal PCR cycling.
- Stop using the cobas Liat System and contact Roche if you suspect either of these two issues has occurred.
Date Published: 15th March 2021
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Note: This content has been edited by a rapidvirology.com staff writer for style and content.
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