A few CPT codes are designated as add-on codes. That is, where applicable, they supplement a primary code; they never stand alone. Let’s examine these codes and how they work.

Q. What are CPT “add-on” codes?

A. According to the 2020 CPT manual, “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 the “+” symbol. Add-on codes describe additional intra-service work associated with the primary procedure. Add-on codes are always performed in addition to the primary service or procedure and must never be reported as a stand-alone procedure. All add-on codes in the CPT code set are exempt from the multiple procedure concept ...”

Q. How do these differ from other CPT codes?

A. For starters, when a code is covered, Medicare payment is made based on 100% of the allowed amount for the physician. It is not reduced by 50%, as are other multiple procedures performed at the same operative session, even when multiple add-on codes are on the claim.

Further, an add-on code is restricted by the requirement to link it to a primary CPT code. Again, it never stands alone. In the ophthalmic surgical section of CPT, most of the add-on codes link to strabismus surgery, but not all.

In 2019, +0514T (intraoperative visual axis identification using patient fixation) was added to CPT. It created a host of questions regarding reimbursement, coverage and usage of an “add-on” code. It is not the only add-on code germane to ophthalmologists; the others are listed in the Table. In Current Procedural Terminology (CPT), add-on codes are identified by a “+” sign preceding the code.

Q. Do add-on codes have allowed amounts?

A. The Medicare Physician Fee Schedule includes payment rates for add-on codes with the exception of temporary Category III codes, such as +0514T, which are determined by the Medicare Administrative Contractor (according to the CMS CY 2020 Physician Fee Schedule Final Rule).

As a relatively new Category III add-on code, +0514T is subject to the administrative vagaries of these temporary codes.

Q. What about for the facility?

A. Unlike physician payment, no separate payment is made for the add-on code for an HOPD or ASC; it’s bundled with the primary code.

For an HOPD, CMS assigned an “N” status indicator to all of the add-on codes, which means, “Items and services packaged into APC rates; paid under Outpatient Prospective Payment System (OPPS); payment is packaged into payment for other services. Therefore, there is no separate APC payment.” (https://www.cms.gov/node/1291136 ). For ASCs, CMS assigned an “N1” payment indicator to the add-on codes, which means the same thing. These bundles cannot be circumvented with an Advance Beneficiary Notice of Noncoverage. OM

Suzanne L. Corcoran is vice president of Corcoran Consulting Group. She can be reached at (800) 399-6565 or www.corcoranccg.com .