Anthem denied my colonoscopy as 'not medically necessary' - ordered by GI after blood in stool for 3 months

I'm still kind of in shock. My gastroenterologist referred me for a colonoscopy after I told him I'd had blood in my stool on and off for about three months. He said given my age (46), family history of colon cancer, and the symptom duration it was absolutely warranted. Put in the pre-authorization. Anthem denied it, saying the colonoscopy is "not medically necessary at this time" and suggesting a non-invasive stool test as an alternative first step.

My doctor is furious. He's already seen the stool test results - I had one six weeks ago and it came back inconclusive. He specifically noted that in the referral. Anthem apparently ignored it or didn't review it carefully. Now I have a denial letter in my hand and a doctor telling me this test genuinely needs to happen.

I know I can appeal but honestly I'm scared of what happens while I'm waiting for an appeal to be reviewed. My doctor mentioned something called an expedited appeal or urgent review given the clinical situation - does anyone know how that process actually works and how fast it moves? I filed a complaint with the appeal process already but I don't really know what I'm doing.