Dermatology Coding Alert

Question: I'm fairly new to dermatology coding and have had problems with reporting add-on codes. Would you please provide some insight into how to use these codes and what dermatology coders need to watch for when reporting these codes?

Minnesota Subscriber

Answer: According to CPT 2004: "Some of the listed procedures are commonly carried out in addition to the primary procedure performed. These additional or supplemental procedures are designated as 'add-on' codes with a + symbol, and are listed in Appendix D of CPT. Add-on codes in CPT can be readily identified by specific descriptor nomenclature which includes phrases such as "each additional" or "List separately in addition to primary procedure."

The add-on code concept in CPT applies only to add-on procedures/services performed by the same physician. Add-on codes describe additional intraservice work associated with the primary procedure, e.g., additional digit(s), lesion(s), neurorrhaphy(s), vertebral segment(s), tendon(s) or joint(s).

Because add-on codes refer to procedures performed in addition to a primary service/procedure, you must never report them as a stand-alone code. All add-on codes found in CPT are exempt from the multiple-procedure concept (see the modifier -51 [Multiple procedures] definition of Surgery Guidelines).

The most common reasons for denials with add-on codes are that coders report add-on codes without a primary procedure. CPT provides parenthetical instructions that usually tell you which codes the add-on code may be used with.

You should study all of the add-on codes used in your practice. Read the complete CPT code description, rather than relying on the limited space on the superbill (also known as an encounter, or charge ticket or a fee slip).

-- Answers to You Be the Coder and Reader Questions were reviewed by Linda Howrey, BS, CCS-P, Howrey and Associates in Princeton, Mass.; and Linda Martien, CPC, CPC-H, National Healthcare Review in Woodland Hills, Calif.