Modifiers are two-character codes (alpha-alpha, alphanumeric or numericnumeric) that may be added to procedure codes to better describe them. Modifiers can greatly impact reimbursement because they indicate that procedures have been altered in some way. For example, �-21� denotes prolonged E/M service, �-24� unrelated E/M service by same surgeon during postoperative period, �-50� bilateral procedures, �-76� repeat procedure by same surgeon, �-51� multiple procedures, and �-53� discontinued (interrupted) procedure. The above are examples of CPT modifiers.

Modifiers may be used with HCPCS Level II codes as with CPT. Some HCPCS modifiers are: � -LT� left side � -FA� left hand, thumb; � -QR� repeat lab test performed on same day; � -SF� second opinion ordered by PRO; � -AF� anesthesia complicated by hypothermia; � -GC� resident services under direction of teaching physician. It should be noted that some codes are single characters, and that some regional carriers do not recognize modifiers due to software limitations. Thus it may be necessary to provide an explanation and/or documentation for appropriate billing.