We require them for treatment of alopecia, corns & calluses, nail debridement, and skin tags, as well as for patch testing when performed for conditions other than dermatitis, and for Unna boot application when done for any conditions other than lower extremity ulcers, varicosities, venous insufficiency, or stasis dermatitis.
If a service is never covered (such as full skin check or cosmetic services), no ABN is required, nor is it necessary to file a claim to Medicare in order to bill the patient. (The only reason you would file a claim and use the GY modifier is if you need to show a Medicare denial, such as for a secondary policy that will pay for services not covered by Medicare.)