Do You Know About Medicare Add-On Code Edits? You Should!

Medicare add-on code edits

Pairing an add-on code with an appropriate primary code is a key factor in bringing in that extra add-on reimbursement. The CPT® manual often provides a listing of appropriate primary codes for an add-on code, but not always. In those cases, you may find answers in Medicare’s Add-On Code Edits, our topic for today.

Know Where to Find Add-On Code Edits

When you see the term National Correct Coding Initiative edits, you probably think of column 2 codes getting bundled into column 1 codes. But if you want to be specific (and as a coder of course you do), those column 1/column 2 edits are Procedure to Procedure (PTP) edits.

Going to the Medicare CCI edits page, you’ll see that Medically Unlikely Edits (MUEs) are also on that page’s left-side menu. And rounding out this list of all-important edits is the link to the Add-On Code Edits page.

Check Type I Add-On Codes When Primary Codes Are Definite

CMS separates the add-on codes into three types. Each add-on code in the Type I group has a limited number of primary codes. The CPT® manual, HCPCS manual, and/or CMS policy defines all of the acceptable primary codes. Your Medicare contractor may pay for the type I add-on code when you report it with a listed primary code for the same practitioner, same patient, and same date of service.

Examples: Add-on code +10004 (Fine needle aspiration biopsy, without imaging guidance; each additional lesion (List separately in addition to code for primary procedure)) is listed in the Add-On Code edits with primary code 10021 (Fine needle aspiration biopsy, without imaging guidance; first lesion). This rule is based on an instruction in the CPT® manual.

Tip: In addition to primary/add-on codes based on CPT® instructions, the Type I list also includes some HCPCS add-on codes with primary codes based on code descriptors. This year, there is also a change report with helpful info like confirmation that 96138 (Psychological or neuropsychological test administration and scoring by technician, two or more tests, any method; first 30 minutes) is a primary code for +96139 (… each additional 30 minutes …). This note is in the file: “No instruction in 2019 CPT® manual – revision in original primary code list approved by email by the CMS NCCI workgroup on 12/6/18).”

Watch for this: If you report critical care, note that Medicare allows you to report +99292 (Critical care, evaluation and management of the critically ill or critically injured patient; each additional 30 minutes (List separately in addition to code for primary service)) without primary code 99291 if another physician of the same specialty in the group practice is paid for 99291 on the same date of service. Here’s an abbreviated version of the example in Medicare Claims Processing Manual, chapter 12, section 30.6.12.I: Drs. Smith and Jones are pulmonary specialists in a group practice. Dr. Smith provides critical care to a patient. Later on the same date, Dr. Jones covers for Dr. Smith and provides critical care services to the patient. Dr. Smith would report 99291 and Dr. Jones would report +99292 assuming they meet the time requirements.

See What Your Contractor Says About Type II

For Type II add-on codes, you won’t find a national list of accepted primary codes. But Medicare encourages claims processing contractors to make their own lists of primary procedure codes for Type II add-on codes.

Examples: Here are some examples of Type II codes:

  • +38747 (Abdominal lymphadenectomy, regional, including celiac, gastric, portal, peripancreatic, with or without para-aortic and vena caval nodes (List separately in addition to code for primary procedure))
  • +0054T (Computer-assisted musculoskeletal surgical navigational orthopedic procedure, with image-guidance based on fluoroscopic images (List separately in addition to code for primary procedure))
  • G0501 (Resource-intensive services for patients for whom the use of specialized mobility-assistive technology (such as adjustable height chairs or tables, patient lift, and adjustable padded leg supports) is medically necessary and used during the provision of an office/outpatient, evaluation and management visit (list separately in addition to primary service)).

Expect Some Uncertainty for Type III

For Type III add-on codes, some primary codes are identified, but not all. The main Add-On Code List defines specifically identifiable procedure codes, but there are other acceptable primary procedure codes. Again, Medicare encourages contractors to develop their own lists of additional primary procedure codes.

Examples: For the codes identified as Type III, Medicare lists acceptable primary codes and adds the note “plus Contractor Defined Primary Code(s)”:

  • +64727 (Internal neurolysis, requiring use of operating microscope (List separately in addition to code for neuroplasty) (Neuroplasty includes external neurolysis)) has non-exclusive primary codes 64702-64726
  • +C9726 (Placement and removal (if performed) of applicator into breast for intraoperative radiation therapy, add-on to primary breast procedure) has non-exclusive primary codes 19301 and 19302.

What About You?

Have you ever reported +99292 without a primary code on the claim for that provider? Did you encounter any problems with the claim?


Deborah works on a wide range of TCI SuperCoder projects, researching and writing about coding, as well as assisting with data updates and tool development for our online coding solutions. Since joining TCI in 2004, she’s covered the ins and outs of coding for radiology, cardiology, oncology and hematology, orthopedics, audiology, and more.

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