How to use surgery modifier 50 bilateral

Definition: Bilateral Procedure; procedures/services that occur on identical, opposing structures (such as for example - "LEFT" and "RIGHT" Side)
Many Billers are still really confused on how Modifier 50 really works. 

APPROPRIATE:

• When performing a procedure bilaterally during one session and the Medicare Physician Fee Schedule BILAT SURG indicator is 1: 
• Report codes with a BILAT SURG indicator of 1 on one line, appending modifier 50 and submit one unit of service. 

For example: 64490 Injection(s), diagnostic or therapeutic agent, paravertebral facet (zygapophyseal) joint (or nerves innervating that joint) with image guidance (fluoroscopy or CT), cervical or thoracic; single level 

Billed as 64490 -50  1 unit

• When performing a procedure bilaterally during one session and the Medicare Physician Fee Schedule (MPFS) BILAT SURG indicator is 3: 
• Submit codes with a BILAT SURG 3 on one line appending either modifier 50 using one unit of service (UOS); or 
• Submit codes on one line with two UOS (the use of the RT/LT modifiers would be optional); or 
• Submit on two lines of service using RT on one line and LT on the other with one UOS each.

INAPPROPRIATE:

• Reporting this modifier when performing the service on different areas of the same side of the body. 
• The BILAT SURG indicator is 0, 2, or 9. 
• When removing a lesion on the right arm and one on the left arm - use the RT and LT modifiers. 
• Do not use modifier 50 for multiple procedures on one organ, such as the skin. 
• On a procedure code that is described as bilateral or unilateral or bilateral in its CPT description. 
• Do not report a bilateral procedure on two lines of service appending modifier 50 to the second line of service.

Coding Tip:
Generally speaking, the above information applies when two of the same procedure codes are performed on the same day for the same patient by the same provider. However, there could be instances where two separate procedure codes are used. If so, Medicare's payment or denial would depend on any other type of rules or regulations concerning the individual services in question. This could include the National Correct Coding Initiative (NCCI) that could necessitate additional modifiers, duplicate edits, and global surgery edits.

Remember, the Modifier 50 is used as a payment, rather than informational, modifier. The addition of this modifier could affect payment depending on the procedure code and the BILAT SURG indicator. The BILAT SURG indicator for each procedure code can be found on the Medicare Physician Fee Schedule Relative Value File. Following are the indicators and their descriptions.

BILAT SURG indicator "0" =150% payment adjustment for bilateral procedures does not apply. If procedure is reported with modifier -50 or with modifiers RT and LT, base the payment for the two sides on the lower of: (a) the total actual charge for both sides and (b) 100% of the fee schedule amount for a single code. Example: The fee schedule amount for code XXXXX is $125. The physician reports code XXXXX-LT with an actual charge of $100 and XXXXX-RT with an actual charge of $100. Payment should be based on the fee schedule amount ($125) since it is lower than the total actual charges for the left and right sides ($200). The bilateral adjustment is inappropriate for codes in this category (a) because of physiology or anatomy, or (b) because the code description specifically states that it is a unilateral procedure and there is an existing code for the bilateral procedure.

BILAT SURG Indicator "1" =150% payment adjustment for bilateral procedures applies. If the code is billed with the bilateral modifier or is reported twice on the same day by any other means (e.g., with RT and LT modifiers, or with a 2 in the units field), base the payment for these codes when reported as bilateral procedures on the lower of: (a) the total actual charge for both sides or (b) 150% of the fee schedule amount for a single code. If the code is reported as a bilateral procedure and is reported with other procedure codes on the same day, apply the bilateral adjustment before applying any multiple procedure rules.

Reference Manual:
The CMS Internet-Only Manual, Publication 100-04, Chapter 12 , Section 40.7.B, indicates "If a procedure is not identified by its terminology as a bilateral procedure (or unilateral or bilateral), physician must report the procedure with modifier "-50". They report such procedure as a single line item."

BILAT SURG Indicator "2" =150% payment adjustment does not apply. Relative Value Units (RVUs) are already based on the procedure being performed as a bilateral procedure. If the procedure is reported with modifier -50 or is reported twice on the same day by any other means (e.g., with RT and LT modifiers or with a 2 in the units field), base the payment for both sides on the lower of (a) the total actual charge by the physician for both sides, or (b) 100% of the fee schedule for a single code. Example: The fee schedule amount for code YYYYY is $125. The physician reports code YYYYY-LT with an actual charge of $100 and YYYYY-RT with an actual charge of $100. Payment should be based on the fee schedule amount ($125) since it is lower than the total actual charges for the left and right sides ($200).

The RVUs are based on a bilateral procedure because (a) the code descriptor specifically states that the procedure is bilateral, (b) the code descriptor states that the procedure may be performed either unilaterally or bilaterally, or (c) the procedure is usually performed as a bilateral procedure.

BILAT SURG Indicator "3" = the usual payment adjustment for bilateral procedures does not apply. If the procedure is reported with modifier -50 or is reported for both sides on the same day by any other means (e.g., with RT and LT modifiers or with a 2 in the units field), base the 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% of the fee schedule amount for each side. If the procedure is reported as a bilateral procedure and with other procedure codes on the same day, determine the fee schedule amount for a bilateral procedure before applying any multiple procedure rules. Services in this category are generally radiology procedures or other diagnostic tests which are not subject to the special payment rules for other bilateral surgeries.

BILAT SURG Indicator "9" = The bilateral payment adjustment concept does not apply.

Ambulatory Surgical Centers (ASCs) and Modifier 50

Bilateral surgical procedures furnished by certified ASCs may be covered under Part B. While use of the 50 modifier is not prohibited according to Medicare billing instructions, the modifier is not recognized for payment purposes and if used, may result in incorrect payment to ASCs.

Bilateral procedures should be reported as a single unit on two separate lines or a single unit with "2" in the unit field on one line, in order for both procedures to be paid correctly. The multiple procedure reduction of 50 percent will apply to all bilateral procedures subject to multiple procedure discounting.

Read more examples for appropriate billing procedures in the MLN Matters article,

"Revised Payment System for Ambulatory Surgical Centers (ASC) in Calendar Year (CY) 2008"  (Revised SE 0742).

References:
CMS: https://www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Downloads/clm104c12.pdf
Noridian: https://med.noridianmedicare.com/web/jeb/specialties/surgery/bilateral-surgery
American Medical Association Coding Guidelines