You may reach out to a company called Naveris, who has a blood test for post treatment HPV
related head and neck cancer patients, if that applies to you. The test is called NavDx and It may be free, regardless of your insurance. But things could change, so I would ask them to explain how the billing works. I think it would have to be prescribed by a doctor, who has supporting information from your treatments.
I have taken the test, and they sent someone to my home to take the sample.