Modifiers. Modifiers are used in addition to a CPT code to add more information on the claim. These modifiers state special circumstances that affect the amount the physician will be reimbursed. Modifiers are used for evaluation and management, as well as, procedure codes.odifier -80 states an assistant surgeon performed the procedure and -81 identifies a minimum assistant surgeon. Modifiers -90, -91, -92 refer to pathology and lab tests. A -99 modifier is used to show that multiple modifiers are being used on the claim, and is used only on the first CPT code listed on the claim.