The FDA has flagged two issues with Thermo Fisher Scientific’s molecular diagnostic for COVID-19 that could lead to inaccurate results.
The company’s TaqPath kit was one of the first commercial coronavirus tests granted an emergency authorization by the agency, in mid-March. Since then, the test has served as the basis for several COVID-19 diagnostics—including at-home sample collection kits developed by Rutgers University and P23 Labs, among other assays—and has been used with validated modifications.
In an alert to clinical laboratory staff and healthcare providers, the agency pointed to insufficient mixing of samples linked to inadequate vortexing and centrifugation of the test’s RT-PCR reaction plates, which can cause false positive results. Thermo Fisher has updated the kit’s instructions to reduce the risk, affecting the test itself and any associated versions.
A second issue was traced to the assay’s internal positive controls and the software used to interpret results on the company’s Applied Biosystems instruments—which are also widely employed by other FDA-authorized coronavirus test kits.
The agency recommended that lab staff promptly update the device’s software to a newer version and complete a digital tutorial on its use as well as review the amplification curves for all positive results to determine whether a plate should be retested. The FDA also urged routine plate level checks to ensure accuracy.