“…Additionally, the Omicron sublineage BA.2 (not carrying the del69/70 mutation) does not show S-gene dropout ( 7 ). Thus, as for Alpha or Delta variants ( 9 – 11 ), N-gene dropout, which may be qualified as a shift in the N-gene cycle threshold ( C T ) value compared to other target genes’ values, in multiplex PCR assays could be a valuable indicator of the Omicron variant. Consistently, Omicron variant-defining mutations, such as P13L, E31del, R32del, S33del, R203K, and G204R in the N protein, could lead to N-gene target failure in PCR assays that target the N gene.…”