On Jan. 14, 2021, Twist Bioscience announced that it had started shipping its new synthetic RNA reference controls, which included the new variant strain of SARS-CoV-2 identified in the United Kingdom.

With this new strain (B1.1.7 lineage, variant under investigation VUI-202012/01), which contained multiple mutations in the spike protein and other areas of the viral genome, some of the RT-PCR probes used widely in COVID-19 testing no longer detect the S gene that codes for the spike protein. This lead to false negative test results.