Outpatient Facility Coding Alert

Question: Should I use code G0279 to bill out a unilateral tomosynthesis with a 77065? If so, should I apply a LT/RT modifier to it to tell the payer that it’s a unilateral service?

Idaho Subscriber

Answer: Since 77065 (Diagnostic mammography, including computer-aided detection (CAD) when performed; unilateral) is inherently a unilateral procedure, you might think that a respective unilateral tomosynthesis code may exist to compliment 77065. However, there is actually only one tomosynthesis code, G0279 (Diagnostic digital breast tomosynthesis, unilateral or bilateral (list separately in addition to 77065 or 77066), which is applicable for both unilateral and bilateral services.

As you can see in the code description for G0279, it’s outlined as a “unilateral or bilateral” code. Therefore, the code is applicable for both bilateral and unilateral circumstances. However, in order to determine whether you should apply a LT (Left side) or RT (Right side) modifier to G0279, you must have a firm understanding of how the bilateral indicator system works. The bilateral indicator system, in short, assigns a specific modifier to a CPT^® code to tell you whether a bilateral or unilateral modifier is applicable.

You can determine a code’s bilateral indicator by looking it up in the Medicare Physician Fee Schedule (MPFS). Here, you will see that G0279 has a bilateral indicator of 2. This essentially means that the code is not eligible for a special payment for bilateral services.

You will find that codes with bilateral indicators of 2 have the terms “bilateral” or “unilateral or bilateral” in their code descriptions. Therefore, CMS guidelines do not allow you to report modifier 50 (Bilateral procedure) with any code with a bilateral indicator of 2. However, you may still add individual LT and RT modifiers, for unilateral services. So, in this case, you will simply report these services as 77065 and G0279 (with an LT or RT, depending on laterality).

Look out: Keep an eye out for an upcoming issue of Outpatient Facility Coding Alert for a complete breakdown on bilateral indicators and how they might affect your coding and reimbursement.

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