Modifiers added to an HCPCS or CPT© code alters the code description, providing clarity about the service for proper claim processing and reimbursement. Here are four things you must know about modifier 50 to ensure proper payment. 

1. Modifier 50 is a payment modifier, meaning it changes the amount of money normally reimbursed for the service it is added to.

Modifiers are either informational or payment related.

• Informational modifiers provide additional details about the procedure or service, such as modifier OD, which explains the service was performed only on the right eye.
• Payment modifiers inform the payer that an adjustment to the normal payment rate may be required. For example, adding modifier 50 to a unilateral procedure code indicates it was performed bilaterally, thus requiring an additional payment for the second procedure.

Due to the Multiple Procedure Payment Reduction (MPPR) program, Medicare reduces payment by 50% for all additional procedures beyond the first when performed during the same encounter. When modifier 50 is added to a procedure, the code is reimbursed at 150% of the Medicare allowable.

NOTE: The sequencing of modifiers matters. Payment modifiers should always be sequenced before informational modifiers.

2. Modifier 50 can only be reported with certain HCPCS and CPT© codes, which can be identified by indicators 0-3 and 9 in the Medicare Physician Fee Schedule (MPFS) as follows:

Indicator	Description	Example
0	The code is not eligible for modifier 50 because the code is a unilateral service and there is a specific code for reporting the bilateral service.	11200 Removal of 1-15 skin tags, any area Rationale: Code is based on number of tags, not laterality.
1	The code is eligible for bilateral modifier 50 and may be paid at 150% of the fee schedule amount for the single side.	23101 Shoulder joint surgery Rationale: The human body normally has two shoulders and the code describes a unilateral procedure.
2	The code is not eligible for modifier 50 because it is already stated as a bilateral procedure and it is expected to be performed on both sides already.	58900 Biopsy of ovary, unilateral or bilateral Rationale: The code description states the same code is reported if done unilaterally or bilaterally.
3	The code is not eligible for modifier 50 because it is a diagnostic test (70000 or 90000 series code) that is not subject to special Multiple Procedure Payment Reduction (MPPR) rules.	73620 X-rays of foot (2 views) Rationale: If the same x-ray was performed bilaterally, it should be reported on two claim lines as: 73620-RT and 73620-LT, each with one unit of service.
9	Concept doesn’t apply.	80348 Drug screening buprenorphine Rationale: Laboratory testing and other types of services don’t qualify as a bilateral service.

Note: Indicators can be found in Find-A-Code by clicking on the "Additional Code Information" tab on the code page.

3. Payer-specific reporting can make or break reimbursement.

Medicare requires modifier 50 to be reported with eligible codes on a single claim line (e.g., 20550-50). Some private payers follow Medicare reporting guidelines while others may require bilateral services to be reported on separate claim lines with right and left modifiers (e.g., 20550-RT, 20550-LT). 

Knowing what each payer requires can save a lot of time, frustration, and reduce financial losses. After performing an internal audit to verify how various contracted payers were reimbursing for modifier 50, one surgical practice identified hundreds of bilateral claims that had only been reimbursed as if they had been performed unilaterally. Further investigation revealed the one specific payor required RT and LT modifiers in place of modifier 50 only because their claims processing software could not process 150% of reimbursement with modifier 50 and required individual claim lines instead. In this particular case, the provider was able to recoup these payments within the timely filing deadlines due to good internal auditing practices and coding protocols for that specific payor were updated to avoid future losses. However, if the practice had not been doing their internal audits they would have missed the timely filing deadlines, resulting in significant financial losses. 

4. As of January 1, 2020, you will no longer be able to report modifier 50 with add-on codes.

Add-on codes describe services that are always performed in conjunction with a primary service by the same provider in the same encounter or patient session. The only exception to this is for reporting critical care services (99291 and 99292), which may be reported by another provider within the same group practice at different encounter sessions on the same date. 

The Medicare Physician Fee Schedule (MPFS) identifies the global periods for add-on codes with indicator ZZZ, which means they have the same global period as the primary procedure they are reported with. 

Reporting modifier 50 for eligible add-on codes has been a common practice until now. Effective January 1, 2020, all add-on codes will no longer be eligible for modifier 50 due to changes in the CPT© codebook. The only way to report these services now will be to use both modifier RT and modifier LT on separate lines as seen in the following example:

Scenario: Diagnostic facet joint injection using dexamethasone into bilateral C3-4 and C4-5 facet joints. 

Codes: 64490-50, 64491-RT, 64491-LT

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