Can anyone clarify for me exactly what the SG modifier is still used for? All specific circumstances would be greatly appreciated. Would a non-standard bill for a facility fee where the CPT code is used as the facility fee billed 64479-SG an acceptable AAPC billing code? We have seen a lot of non-standard billing with pain management where the facility fee is is billed with the CPT code from a ASC that is connected with the surgeon. Is a 64479-SG an acceptable billing - exclusive of the UB04 or CMS1500 forms? They are not using these forms of billing. Also, does anyone have any idea why they prefer to bill their facility fees this way? Thank you!