@teintnatural, I know this is the last thing that you want to be dealing with at this time. If you don't get a resolution from your provider, please reach out to Castle Biosciences (https://castlebiosciences.com/resources/test-reimbursement-2/). These companies are used to dealing with denials. This type of biomarker testing is helpful in determining the driver of many cancers today, but many insurance companies will deny claims. The results of these tests can drive treatment decisions.
I had this type of test for lung cancer. At the time, I wasn't aware that the test was being sent to a third-party lab. The results of the test were very beneficial for me, I am thankful that the tests were run. My insurance carrier denied the claim as 'experimental', even though many states are passing legislation requiring payment for this type of testing. After the denial, I did receive a letter from the biomarker testing company, they fought for payment on my behalf. I did have to authorize them to do that, but then I never heard anything about it again. So, either the insurance company paid, OR the company waived the fee. Best of luck to you.