ahm's GapCover is designed to help eliminate or reduce out-of-pocket expenses for in-hospital doctors' charges. Doctors can choose to participate in GapCover on a claim-by-claim basis. So it is important to check upfront with each doctor involved in a treatment if they will participate in GapCover for all of their claims. Out-of-pocket costs may still apply. GapCover doesn't apply to diagnostic services or to some other services.