Procedure not covered

 Why would AARP cover your medical, It's not clear.  

@BettyL689193 

What is the name on your policy ? The actual name of the policy - AARP/UHC what?   Is it a Medicare Advantage plan or one of the many Medigap (Medicare Supplemental) plans.  AARP/UHC sells both types of coverage under Medicare and they are completely different.  

Nobody can answer your question or give you any guidance without specifics of the plan but AARP is not the insurer - UHC is the insurer.  It bears AARP name only because of its marketability.  

Your question about coverage would be more swiftly answered if you contacted the insurer - UHC - about your plan - or somebody to explain your plan to you after it has been identified.  

If you have original medicare and a supplement: The rules with supplements is that if medicare covered it then your supplement is supposed to cover it to the extent that your particular supplement covers things taking into account your deductible (if it already hasn't been met). Talk with your hospital billing office (and if you get no satisfaction to their patient advocacy department) as it may be they sent in the claim at the same time they sent in the medicare A or B claim. Medicare has to pay before a supplement will pay. 

I don't know how advantage plans handle this so you'd have to contact that plan to find out. I do know they have pretty high maximum out of pockets you have to pay. If you have an advantage plan that may be why you have to pay that large amount.

While AARP associated with united health care (UHC), AARP is not an insurance company, uUHC would be your insurance company so call UHC.