Bilateral Indicators and Billing Guidelines


Bilateral Indicators

Bilateral procedures are those that are performed at the same operative session by the same physician on bilateral body structures (identical anatomic sites on opposite sides of the body). Bilateral modifiers include 50, RT, and LT. CMS NCCI rules and bilateral indicators dictate the procedures that are subject to bilateral billing and bilateral payment policy. Also, CPT guidelines, Medicare guidelines, and payer policies can vary and as such, it is necessary to bill bilateral services as these policies dictate. Individual payer bilateral billing and payment policies can be found on our Bilateral Billing Guide.

The CMS Medicare Physician Fee Schedule Data Base (MPFSDB) and the Novitas Fee Schedule search tool provide bilateral indicators identifying procedures eligible for bilateral billing (see screen shots below). Only CPT codes with an indicator of “1” or “3” are eligible for bilateral billing. The bilateral indicators are as follows:

  • 0 - Do NOT use modifier 50. These CPT codes specifically state that they are a unilateral procedure and another code for bilateral procedures exists, or they are a unilateral or bilateral procedure because of anatomy or physiology.
  • 1 – May use modifier 50. These procedures are unilateral and can be performed on identical anatomical sites, aspects, or organs. In general, payment will be made at 150% of the allowed amount.
  • 2 - Do NOT use modifier 50. The CPT code descriptors state that the procedure may be performed either unilaterally or bilaterally and as such, payment is already based on the procedure being performed bilaterally.
  • 3 - May use modifier 50. These are typically non-surgical services (e.g., Radiology and some Diagnostic testing codes). When performed bilaterally, in general payment will be made at 200% of the allowed amount.
  • 9 - Do NOT use modifier 50. The bilateral concept does not apply to these codes.


Bilateral billing indicator examples:
     
     Novitas:

          

     
     MPFSDB:

          



Medically Unlikely Edits

The NCCI Medically Unlikely Edits (MUEs) also have an impact on bilateral billing and payment policy and may render certain bilateral services ineligible for payment if billed incorrectly. MUEs are the maximum units of service for a particular CPT code that can be billed by the same provider for the same beneficiary on the same date of service. The National Correct Coding Initiative (NCCI) manual specifies that modifier 50 is used to report bilateral surgical procedures as a single unit of service and warns that MUE edits may limit units of service. Consequently, many bilateral procedures have an MUE value of 1 unit. If a CPT code has an MUE of 1 unit, billing it in excess of 1 unit will result in a denial or reduced payment. In the incorrect billing examples below, CPT 15823 has an MUE of 1 unit but 2 units have been billed. As such, rather than being paid at 150% of the allowed amount, payment will likely be reduced or denied altogether.

Incorrect billing:

     

When a CPT code has an MUE of 1 unit, bilateral services cannot be billed in such a manner that exceeds 1 unit. In the example below, the correct billing for 15823 performed bilaterally is to bill the service on 1 claim line with modifier 50 appended at 1 unit. When billing bilateral services in this manner, remember to double the charge for the bilateral service as the bilateral service will pay at the lesser of  the amount billed or 150% of the allowed amount (100% for one side, and 50% for the other side).

Correct billing:

     

 

Payer Billing and Payment Policies

Payer policies vary as to when to use modifiers 50, LT, and RT and at what rate bilateral procedures will be paid. Depending on a payer's policy, bilateral procedures may be paid at 100%, 150%, or 200% of the allowed amount. In general:

  • Procedures performed bilaterally with a bilateral indicator of "1" are generally paid at 150% of the allowed amount (100% for one side, and 50% for the other side). In general, such procedures should be billed on 1 line, with modifier 50, at 1 unit, at twice the charge.
  • Procedures performed bilaterally with a bilateral indicator of "3" are generally paid at 200% of the allowed amount (100% for each side). In general, such procedures should be billed on 1 line, with modifier 50, at 1 unit, at twice the charge.
  • Procedures with "bilateral" in the CPT code description are already being paid as if performed bilaterally and will pay at 100% of the allowed amount. As such, appending modifier 50 would be inappropriate. Should the procedure be performed on only one side (unilaterally), modifier 52 (reduced services) should be appended. Depending on the payer, a LT or RT modifier may also be required to report the side in which the procedure was performed. 
  • Procedures with "unilateral or bilateral" in the CPT code description are also already being paid as if performed bilaterally and will pay at 100% of the allowed amount. As such, appending modifier 50 would be inappropriate. Should the procedure be performed on only one side (unilaterally), modifier 52 (reduced services) may be required along with a LT or RT modifier to report the side in which the procedure was performed. 

Many payers do not have specific billing instructions for the above 4 scenarios. However, following each payers’ bilateral billing policies when available will help to ensure timely and accurate processing of bilateral claims. If specific guidance is not provided, bill for the services as outlined above and closely monitor how the payer processes these claims to ascertain their preference. Our Bilateral Billing Guide provides the bilateral billing and payment policies for most of the payers in the Houston market with links to each if available. 

*Please note that the content provided herein is informational only, and should NOT, in any way, be considered legal, professional, business, practice, insurance, or other advice.  Nor should any information found herein be considered a referral, endorsement, guarantee, or promotion for any specific course of action or inaction. Please do your research and consult your own practice adviser or attorney before taking any action or inaction based on this information.