Review Progress of CV testing in the US

The mutations are often slight and probably have little effect on the ability to test for the virus. A vaccine might cause more adaptations but other RNA viruses have not been affected by vaccines (measles, mumps) in terms of their mutation.

But whatever anyone says, from the laboratory experts to the armchair 'experts', every new virus is an unknown - so what happens in the case of SARS-Cov-2 is yet to be found out.

 

Regarding the in-office Labcorp anti-body testing (to test if you had a previous, not current Covid-19 infection), I can confirm it's readily available in the US. I just had the test on Monday.
The test has no co-pay if you have US health insurance. I believe that's built in to the Covid stimulus/aid bill that passed here. If you don't have health insurance I believe the federal govt. will cover it through Medicaid.
You can either get a referral from your doctor or Labcorp has partnered with telemedicine group that will give you an online referral after answering a few simple qualifying questions and paying a $10 fee.
Since we're in Pennsylvania temporarily but our doctors are in Florida, that was the easiest route for us.
Enter your personal and insurance data on the Labcorp site and schedule an appointment at one of their many offices for a blood draw. There were plenty of time slots available, I scheduled for the next day after I signed up.
I got my results back the next day, and was a little disappointed that they were negative.
https://www.labcorp.com/antibody-testing

 

The US govt issued a clarification that antibody testing is covered.
https://www.cbsnews.com/news/coronavirus-antibody-testing-covered-free-health-insurance-medicaid/