I haven’t used Costco, so I can’t vouch for how they do it, but my expectation is they do. To my knowledge, (almost all, I’m sure there may be exceptions out there) medical insurance carriers, including Medicare, will cover the cost of testing as a diagnostic procedure if ordered by an ENT doctor, even if they don’t cover HAs themselves. A standard diagnostic audiogram by definition would need WRS or be considered inadequate for diagnosis and not be reimbursed.
To get my insurance to cover one HA (guess they figure one is better than none) I first had to see an ENT doc. It was appropriate, as I had seriously impacted cerumen in both ears that needed two sessions to clear (vacuumed once, then a week of peroxide drops to soften up the crap still stick to my eardrum and another vacuuming, no way to properly test my hearing without that done). Then I had a referral to the Aud for an audiogram and evaluation for my hearing loss. They covered the ENT visits, audiology “consult” and testing. Then the Aud was able to make a recommendation of a HA based on what my insurance would cover. I ended up having to pay for the second HA myself, but it beat paying for two.
Obviously not everyone sees an ENT doc before getting HAs. But even if you go for evaluation of your hearing to an Aud and get an audiogram, that cost can reimbursed if you’re billed for it. Folks can check with their carrier and ask the Aud for a bill to submit, but typically if you’re walking in and heading straight to a HA purchase, or even a “consult” for one, the Aud will just view that as a free service and not bill. It might still be worth asking about splitting that out to get at least something back, even if you’re not covered for HAs themselves.