The U.S. Food and Drug Administration (FDA) issued an alert to clinical laboratory staff and healthcare providers about a risk of false results with Thermo Fisher Scientific's TaqPath COVID-19 Combo Kit based on two issues related to the test kit and the associated Applied Biosystems COVID-19 Interpretive Software, according to a press release from the agency.
The test is designed to detect viral nucleic acid from SARS-CoV-2, the virus that causes COVID-19, in upper respiratory specimens, such as nasal swabs. The FDA said there are two issues.
The first issue is related to inadequate vortexing and centrifugation of RT-PCR reaction plates. The FDA said Thermo Fisher Scientific’s conclusion from investigations of customer complaints indicate that inadequate vortexing or centrifugation can lead to false positive results. To solve the problem, Thermo Fisher Scientific has updated its instructions to reduce the risk of inaccurate results.
The second issue is related to the assay Internal Positive Control (IPC). To solve this problem, lab employees need to upgrade their software to reduce the risk of invalid, potential false negatives, or inconclusive tests and to decrease the potential need to retest.
Specifically, the agency said labs should stop using Applied Biosystems COVID-19 Interpretive Software v1.2, v2.0 and v2.2 and upgrade to Applied Biosystems COVID-19 Interpretive Software version 1.3 or 2.3. The agency noted that lab employees will need to complete training and pass an exam to upgrade the software. Lab personnel should read and implement the vortexing and centrifugation instructions Thermo Fisher Scientific added to the latest release of the Instructions for Use to prevent insufficient mixing and/or centrifugation.
For all positive results, the FDA said labs should review the amplification curves within the instrument software for controls and patient specimens to determine whether the plate should be retested due to inadequate vortexing and centrifugation. Labs should contact their local Thermo Fisher Scientific Field Applications Scientist for additional information on viewing amplification curves and performing plate level checks.
The FDA also said labs should implement routine plate level checks of the amplification curves to ensure labs appropriately adhere to specimen processing instructions for vortexing and centrifugation.
