A bit OT, but here goes (and Watching, because my 4 antigen tests are presumably in the mail):
Are they going to have a means to test if you are exposed to Omicron specifically? It would seem to be possible.
It is highly unlikely to be doable with antigen tests. Antibodies just are not specific enough. Think of an antibody like a Lego piece. Imagine you have one Lego piece and try to stick it to anything you can find. The Lego piece for the most part is specific enough to only stick to other Lego pieces. It doesn't stick to your couch, or fridge, or pet. But, that Lego piece does stick to many different other Lego pieces. So, it is specific enough to know that if it stuck you have found another Lego, but it can't tell which specific Lego you found.
With PCR you certainly can determine which strain you have. But, as the number of mutations Covid has keeps increasing, PCR just gets really complex to look for all of them.
Sequencing is best once you have a large number of mutations to look for. But, despite the cost of sequencing plummeting in recent years, it is still quite expensive so it is only done occasionally to see what strains are common in the area.
But honestly, the easiest thing we have right now is just your symptoms and timing of what variant is common in your area. Omicron has symptoms like a cold, the other variants (so far) have symptoms like a flu. Those should be pretty easy to tell apart without any tests needed.
- If you test positive and have some of these: a dry cough, shortness of breath, fever/achiness, or loss of taste/smell then you almost certainly have Delta.
- If you test positive and have some of these: sneezing, congestion, night sweats, sore throat (especially if it was one of the first symptoms) then you almost certainly have Omicron.
- Note: you have to be honest with your symptoms here. Many people who claim to be asymptomatic actually had symptoms that they try to explain away (such as "I have a cough due to smoking, thus these extra coughs are not Covid").