Bring in Correct Bilateral Procedure Pay With These Pro Pointers

report bilateral surgeries using codes and modifiers

Choosing medical codes and modifiers for bilateral services can be confusing. Here are a few questions you can ask to help ensure accurate coding and reimbursement for physician claims.

Does the Code Descriptor Specify Bilateral?

“Bilateral surgeries are procedures performed on both sides of the body during the same operative session or on the same day,” states the Medicare Claims Processing Manual (MCPM), chapter 12, section 40.7.

One of the first steps in deciding how to report a bilateral service is to see whether the code itself represents a bilateral service. The official code definition may state the code applies to services that are unilateral, bilateral, or both.

Example: Note the phrase “unilateral or bilateral” in eye code 92025 (Computerized corneal topography, unilateral or bilateral, with interpretation and report). That means that whether the service is unilateral or bilateral, code 92025 applies. For a bilateral service, appending modifier 50 (Bilateral service) or appending both RT (Right side) and (Left side) would be inappropriate because in this case the code itself already represents a bilateral service.

Tip: Appending modifier 50 to a code that specifies “unilateral” may be correct, but first you need to confirm that there is not a code for a bilateral version of the same service that you should use instead.

What Is the MPFS Bilateral Indicator for the Code?

Another way you can confirm whether the code represents a bilateral service is to check the Medicare Physician Fee Schedule (MPFS) bilateral indicator (assuming the CPT® or HCPCS code is in the MPFS).

For our example eye code from above, 92025, the MPFS bilateral indicator is 2, meaning the code is already priced as bilateral. You can see the definition in the list of bilateral indicators below (these are abbreviated versions of the full definitions in MCPM, chapter 23):

  • 0: 150 percent payment adjustment for bilateral procedures does not apply. If a procedure is reported with modifier 50 or with modifiers RT and LT, Medicare bases payment for the two sides on the lower of: (a) the total actual charge for both sides or (b) 100 percent of the fee schedule amount for a single code.
  • 1: 150 percent payment adjustment for bilateral procedures applies.
  • 2: 150 percent payment adjustment for bilateral procedure does not apply. RVUs are already based on the procedure being performed as a bilateral procedure.
  • 3: The usual payment adjustment for bilateral procedures does not apply. If procedure is … reported for both sides on the same day … Medicare bases payment for each side or organ or site of a paired organ on the lower of: (a) the actual charge for each side or (b) 100 percent of the fee schedule amount for each side.
  • 9: The bilateral surgery concept does not apply.

To sum up, do not use modifier 50 on codes with 0, 2, or 9 bilateral indicators. Modifier 50 may be appropriate for bilateral services reported using codes with indicators 1 or 3. But note that codes with indicator 3 may be radiology services or diagnostic tests, so there may be a more appropriate reporting method than using modifier 50. (Read the next section for more on the 50 or RT/LT question.)

Tip: The MPFS bilateral indicator may surprise you sometimes, so don’t make assumptions. For instance, unilateral is in the descriptor of 69210 (Removal impacted cerumen requiring instrumentation, unilateral), but MPFS gives it a bilateral indicator of 2, meaning that appending modifier 50 won’t increase your reimbursement. Keep in mind that MPFS is from Medicare, so a non-Medicare payer may have a different rule.

Should You Use 50 or LT/RT?

If a code descriptor does not specify that the code represents a bilateral service and you’ve confirmed the bilateral indicator, then you should use a modifier to report the bilateral service. The MCPM states that for Medicare claims you should report the code as a single line item with modifier 50 appended.

The MCPM goes on to instruct Part A/B MACs that they have to be able to do these things (among others):

  • Identify bilateral surgeries by either modifier 50 OR the same code on separate lines with LT on one and RT on the other.
  • Check the bilateral indicator and calculate payment accordingly.

Because Medicare mentions RT and LT, you may wonder when you should use them instead of modifier 50. The general rule is that if you’re reporting a truly bilateral surgery, you use modifier 50. But you also should check your specific payer policy on modifier 50 and LCDs for your services. You may luck into a modifier 50 fact sheet like WPS GHA has for its Part B providers.  Watch for rules in your payer policy like “Do not use modifier 50 for multiple procedures on one organ, such as the skin” and “When removing a lesion on the right arm and one on the left arm – use the RT and LT modifiers,” which are quotes from the WPS fact sheet.

Did You Remember ICD-10-CM?

Don’t forget to support your bilateral service with the appropriate ICD-10-CM diagnosis code or codes. Many ICD-10-CM codes have specific options for bilateral conditions. Be sure to apply the correct ICD-10-CM code based on the documentation, payer rules, and the official ICD-10-CM guidelines.

What About You?

What approach do you follow to help you decide how to code services performed on both sides of the body?


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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