Avoid the Top 10 Modifier Mistakes – Modifier 51

Matching CPT code with an ICD 10 code, would seem to be a very straightforward process but there are always variations/exceptions to everything. Sometimes, there are related services that the physician is performing, global periods to contend with, etc. Modifiers will clarify extenuating circumstances, which should allow for payment when they otherwise may not. That said, the improper use of modifiers can be the cause of claim denials just as not using a modifier can be. When using modifiers, make sure you clearly understand what the modifier entails.

In this, and the following blogs, we identify 10 of the most commonly misused modifiers to help you become more aware of the issues surrounding them. We’ll help you understand why they are problematic and how you can use them correctly.

Modifier 51

Modifier 51 is defined as multiple surgeries/procedures. Multiple surgeries performed on the same day, during the same surgical session.  Diagnostic Imaging Services subject to the Multiple Procedure Payment Reduction that is provided on the same day, during the same session by the same provider. Medicare doesn’t recommend reporting Modifier 51 on your claim; our processing system will append the modifier to the correct procedure code as appropriate.

How it’s misused: This modifier can be misused in several different ways. First, you can incorrectly apply it when a procedure is more accurately described with an add-on code. Also, you should not use it with an evaluation and management (E/M) service. And finally, you might incorrectly apply it to the wrong procedure, especially if you are billing claims for Medicare.

Inappropriate Usage:

  • Do not append to add-on codes (See Appendix D of the CPT manual)
  • Do not report on all lines of service
  • Do not append when two or more physicians each perform distinctly, different, unrelated surgeries on the same day to the same patient.

Appropriate Usage:

The Modifier is appended when:

  • The same physician performs more than one surgical service at the same session (Indicator 2).
  • The technical component of multiple diagnostic procedures, the Multiple Procedure Payment Reduction (MPPR) rule applies (Indicator 4).
  • The multiple surgical procedures are done on the same day but billed on two separate claims.
  • The surgical procedure code is the lower physician fee schedule amount.
  • The diagnostic imaging procedure with the lower technical component fee schedule amount.

Example 1: A surgeon performs a 24500 (Closed treatment of humeral shaft fracture; without manipulation) and a 23500 (Closed treatment of clavicular fracture; without manipulation). You would apply the multiple procedures reduction to 23500, which is the lower-paying code (a national Medicare facility fee of $228.24 versus $335.88 for 24500) if your payer requires modifier 51.

Example 2: Colonoscopy (45378) performed at the same session as upper endoscopy (43200). Use modifier 51 on the upper endoscopy (43200) because the RVU’s are lower than the colonoscopy (45378). 45378, 43200-51.

Example 3: The patient presents for removal of a 0.5 cm (as measured by CPT guidelines) malignant skin lesion on the trunk. Layered closure of the resulting wound is performed in the same operative session. The appropriate coding will be, 12031 Repair, intermediate, wounds of scalp, axillae, trunk and/or extremities (excluding hands and feet); 2.5 cm or less (typically 100 percent allowed reimbursement*).

11600-51 Excision, malignant lesion including margins, trunk, arms, or legs; excised diameter 0.5 cm or less (typically reduced reimbursement*).

*Dependent on carrier policy. You should also note that a few carriers may automatically order the procedure codes based on that carrier’s fee schedules.

Modifier 51 should be applied to all other codes when multiple non-E/M services are provided at the same session. Modifier 51 can be used with other modifiers, when appropriate, except modifier 50.