Coding of Add-On Codes

This edition of “Spotlight on CPT” will cover the appropriate coding of add-on codes in CPT. Add-on codes, identified in CPT with the + symbol, note procedures that are commonly performed in conjunction with a primary procedure. Add-on codes capture additional work related to the primary procedure by the same physician during the same encounter. For example, in the integumentary system of CPT, if a physician removes 20 skin tags, the codes reported would be 11200 for the removal of multiple skin tags up to and including 15 lesions, and +11201 for each additional 10 lesions, or part thereof.

In addition to being identified with the + symbol, a list of add-on codes is found in CPT Appendix D. These add-on procedures will also have specific descriptors. Phrases such as “each additional” or (List separately in addition to primary procedure)” are indicative of add-on codes.

One of the most important concepts to remember regarding add-on codes is that they may never be reported without their base or parent code. The most common base codes associated with the add-on code are often provided in an inclusion note following the add-on code. Be advised, that the list of base codes is not exhaustive.

Another key point to keep in mind is that add-on codes may be reported for bilaterally performed procedures. If this occurs, the add-on code should be reported twice unless information in the guidelines, the codes descriptor itself, or a parenthetical instruction for that code directs the coding professional otherwise. Here are examples:

64633  Destruction by neurolytic agent, paravertebral facet joint nerve(s), with imaging guidance (fluoroscopy or CT);

+ 64636     lumbar or sacral, each additional facet joint (List separately in addition to code for primary procedure)

(For bilateral procedure, report 64636 twice. Do not report modifier 50 in conjunction with 64636)

32998  Ablation therapy for reduction or eradication of 1 or more pulmonary tumor(s) including pleura or chest wall when involved by tumor extension, percutaneous, including imaging guidance when performed, unilateral; radiofrequency

+32994     cryoablation

(For bilateral procedure, report 32994, 32998 with modifier 50)

The parenthetical notes following both sets of codes provide clear direction on the appropriate bilateral procedure coding. Always be sure to follow such instruction.

Now, light has been shed on coding of add-on codes.

About the Author

Dianna Foley, RHIA, CCS, CDIP, CHPS, has 25 years of HIM experience. She earned her bachelor’s degree from the University of Cincinnati and holds RHIA, CHPS, CDIP, and CCS certifications from AHIMA. Dianna’s an AHIMA-approved ICD-10-CM/PCS trainer, an AHIMA-published author, a participant in AHIMA credential item writing and exam development, and served on the AHIMA Nominating Committee. Dianna has held various HIM positions and is now an independent coding consultant. She previously served as a program director for Medical Coding and HIT. She presents on coding topics at the national, state, and regional levels and serves as OHIMA’s Education Coordinator.