Started isolating after my brother, who I live with tested positive, and four days later I was also testing positive (making it likely he transmitted it to me). I did a PCR test and the lab returned with the confirmation.

Gen RdRP/ RdRP Gene: 24.72 cts.

Gen S/ S Gene: 22.37 cts.

Gen N/ N Gene: 22.38 cts.

However, my brother had completely different results, which did not include the S-Gene.

Gen ORF1ab/ ORF1ab Gene: 29.81 cts

Gen N/ N Gene: 32.97 cts

What I'm wondering is, do we have different strains? I read that PCR doesn't detect the S-Gene in the omicron variant. The PCR tests were done on different days, so maybe they just used different markers?

We're a bit confused right now and a bit worried since after I tested positive too we started sharing common areas of the apartment again.

  • 1
    This question will likely get closed as it's not intended for individual medial results, but "they just used different markers?" seems correct to me. There are many different PCR tests for Covid, and labs may use multiple ones as part of their testing flow.
    – Armand
    Commented Jan 11, 2022 at 22:28
  • @Armand thank you. Any idea about the S gene popping up? Still unclear if its absence means I don't have omicron
    – Pistachio
    Commented Jan 11, 2022 at 22:37
  • The only way to know for sure is to ask the lab., perhaps their web site or the results printout has more info.
    – Armand
    Commented Jan 11, 2022 at 22:41
  • Orf1ab is the same as RdRP. Lack of S doesn't tell you anything other than they might not have done it. If it was tested and result reported no CT, then it might tell you something about whether you have omicron or another variant with S-gene dropout. Basically different tests done on you and your brother.
    – bob1
    Commented Jan 11, 2022 at 22:51


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