Dermatology Coding Alert

Question: Our dermatologist's  documentation noted that he performed biopsies on two separate lesions. As a result, I reported 11100 and 11101-59 to indicate that the dermatologist performed a distinctly separate procedure. The carrier denied our 11101-59 claim. Would you please explain why this is wrong?

Mississippi Subscriber

Answer: You were denied payment for +11101 (Biopsy of skin, subcutaneous tissue and/or mucous membrane [including simple closure], unless otherwise listed; each separate/additional lesion [list separately in addition to code for primary procedure]) with modifier -59 (Distinct procedural service) because 11101 is an add-on code, and you should not report add-on codes with a modifier. Because it's an add-on code, CPT requires you to report 11101 with another primary code.
 
Therefore, when you report an add-on code, you already notify the payer that the dermatologist performed two different biopsies. The same rule would apply if the dermatologist performs more than two biopsies.

You should never append a modifier to an add-on code. Refer to your CPT manual to see add-on codes marked with "+" designation.