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U.S. regulators have warned of the potential risk for false negative results with molecular testing for SARS-CoV-2 due to mutations such as the recently discovered B.1.1.7 version of the virus.
The U.S. Food and Drug Administration (FDA) on Friday issued a warning to clinical laboratory workers and clinicians. The group warned that false negative results can occur with any molecular test for SARS-CoV-2 detection if there is a mutation in the part of the virus genome that was assessed by that test.
The risk of these mutations affecting overall test accuracy is low, but the FDA is taking additional steps to ensure authorized tests remain accurate, the agency said. These include working with test developers and ongoing data analysis to evaluate all currently authorized molecular tests.
Like all viruses, SARS-CoV-2 was expected to go around the time, as evidenced by the appearance of variant B.1.1.7, the FDA said.
“While these efforts continue, we are working with authorized test developers and reviewing incoming data to ensure that healthcare providers and vendors can clinical work of patients diagnosed with SARS-CoV-2 infection quickly and accurately, including those with emerging genetic changes, “said FDA Commissioner Stephen Hahn, MD, in a press release.
On a positive note, however, he said “at this stage, we believe the data suggest that the currently authorized COVID-19 vaccines may still be effective against this snoring. “
In its Friday letter to healthcare workers, the FDA said its analysis to date has identified three molecular trials that have received emergency use approval (EUA) that could affect the genetic performance of SARS-CoV. -2.
Accula SARS-CoV-2 Test:
The FDA study, including additional information provided by the manufacturer, Mesa Biotech Inc, shows that the performance of this test may be affected when a sample of SARS-virus patients is tested. CoV-2 is genetically differentiated at 28881 (GGG to AAC). “As long as the impact does No seemingly important, the FDA is issuing this warning to healthcare providers out of sufficient notice as we continue to collect additional data and work with the manufacturer, “said the group.
The FDA also advised that healthcare professionals should be aware of updated guidelines for their use for the Accula SARS-CoV-2 Test. These now occupy the exact variable position, in silico analysis of the primer bond, and observed performance impact compared to the perfect matching target.
TaqPath COVID-19 Combo Kit and COVID-19 Line Assay Kit:
The FDA said the detection pattern that emerges with the TaqPath and Linea diagnostic tests when some genetic differences are present may help in the early identification of new changes to further spread disease. reduce.
“The recently identified variant of B.1.1.7 has been associated with an increased risk for transmission, so early identification of this variability in patients may help to further reduce transmission of infection, “the group said.
The group also advised healthcare professionals to be aware of the pattern of detection associated with specific mutations, including the B.1.1.7 variant, in particular a pattern of 2/3 positive targets showing the S-gene release (less sensitivity with the S- gene target), when using the TaqPath COVID-19 Combo Kit, and a pattern of 1/2 positive targets showing the S-gen dropout when using the LineV COVID-19 Assay Kit.
“If local or state clinical laboratories have access to rapid turnaround genome sequence services, such as those using the EUA-authorized Illumina COVIDSeq Test, these laboratories should consider further characterization. sample on a genetic sequence when this pattern is identified, “the FDA said.
If these services are not readily available, laboratories should consider reaching out to the Centers for Disease Control and Prevention (CDC) at [email protected] for additional information, said the FDA.
Other genetic variables
The FDA has also offered the following recommendations for clinical laboratory workers and clinicians who use molecular tests to detect SARS-CoV-2:
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Be aware that genetic modifications of SARS-CoV-2 occur on a regular basis, and false negative test results may occur
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Note that experiments that use multiple genetic targets to determine an end result are less likely to be affected by increased genetic frequency.
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Consider negative outcomes in conjunction with clinical observations, patient history, and epidemiological information
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Consider retesting with a different test (with different genetic targets) if COVID-19 is still suspected after receiving a negative test result
Multiple SARS-CoV-2 mutations are circulating worldwide, according to the CDC. A number of new changes emerged at the end of 2020, including the B.1.1.7 line seen in the United Kingdom. This variation has since been found in many countries around the world, including the United States and Canada.
In South Africa, another variant of SARS-CoV-2 (known as 20C / 501Y.V2 or B.1.351 lineage) has emerged independently of line B.1.1.7, the CDC said. This variable divides some solutes by the line B.1.1.7. The CDC said issues related to this variability have been discovered outside of South Africa.
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