Modifier 51 and Modifier 59 – Know the Differences

by | Published on Jan 4, 2021 | Podcasts, Medical Billing (P)

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An experienced medical billing and coding company in U.S., Outsource Strategies International (OSI) has been providing reliable medical billing services for diverse healthcare specialties. Our team of coders is up to date with changing coding standards.

In today’s podcast, Natalie Tornese, our Senior Group Manager discusses the right usage and differences between Modifier 51 and Modifier 59.

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Hello everyone and welcome to our podcast series. My name is Natalie Tornese and I am the Senior Group Manager for Outsource Strategies International.

I wanted to talk a little bit about two modifiers that are often misused in billing claims. These are -modifier 51 and modifier 59.

00:22 Importance of using right modifiers

Correct and appropriate use of modifiers is important to file accurate claims and to receive correct payments. Modifiers enable providers to effectively meet policy requirements established by the insurers. The wrong use of modifiers is one of the most common coding mistakes. When the same provider performs multiple procedures in the same setting there is often confusion about using modifier 51 or modifier 59. Modifier 51 is for multiple procedures and modifier 59 is for a distinct procedural service. They are both used when multiple services are performed during a single encounter however they serve different purposes.

01:07 Use of modifier 51

Modifier 51 can be used to report multiple surgeries performed on the same during the same surgical session. It is used to identify the second and subsequent procedure to third party payers. The modifier would be applied to any secondary procedures performed. It can be used to document two procedures in two different coding categories performed on the same day. To report this modifier right , the coder should list the procedure with the highest relative value units first and use modifier 51 on the subsequent service with the lower relative value units. The American Society of Anesthesiologists says that modifier 51 applies to

  • different procedures performed at the same session
  • a single procedure performed multiple times at different sites or
  • a single procedure performed multiple times at the same site

It is not to be used when the procedure is performed along with an E/M service. There are instances where multiple procedures are performed but modifier 51 would not be appropriate. For example it is not appended to add-on codes like CPT 64462.

02:23 Use of modifier 59

Modifier 59 refers to a distinct procedural service which indicates that a procedure is separate and distinct from another procedure provided on the same date of service. According to CMS, “Modifier 59 is an important NCCI associated modifier that is often used incorrectly.” Modifier 59 helps to identify procedures /services other than E/M services that are not normally reported together but are appropriate under the circumstances. It can be used for a different session or encounters on the same date of service and different procedures distinct from the first procedure.

To use this modifier, the provider’s documentation has to support different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury, which is not ordinarily encountered or performed on the same day by the same individual. Over use of modifier 59 is an audit target and should only be used if the two codes are bundled,           specifically if there is an NCCI edit for the two codes. CMS recommends that this modifier should only be used to identify clearly independent services that represent significant departures from the usual situation described by the NCCI edits.

CMS reports another three specific appropriate uses for modifier 59 which are as follows –

  • for two services described by timed codes provided during the same encounter only when they are performed sequentially
  • for a diagnostic procedure which precedes a therapeutic procedure only when the diagnostic procedure is the basis for performing the therapeutic procedure
  • for a diagnostic procedure which occurs subsequent to a completed therapeutic procedure only when the diagnostic procedure is not a common, expected, or necessary follow-up to the therapeutic procedure

04:34 Modifier 51 vs. modifier 59

Coders must make sure not to use modifier 59 when a more appropriate modifier is needed. Modifier 51 is for multiple procedures, an extra procedure in the same session or an extra procedure in a different site. Modifier 59 is a distinct procedure, separate procedure in different sessions or distinct procedure at a different site. While these are the differences in the usage between modifier 51 and 59, there are certain similarities too. For example, both the modifier should not be applied to an E/M service and both the modifiers have payment implications. Modifier 51 impacts the payment amount and modifier 59 affects whether this service will be paid at all.

I hope this helps, but always remember that documentation and a thorough knowledge of payer regulations and guidelines is critical to ensure accurate reimbursement for the procedures performed.

Thank you for listening!

Natalie Tornese

Holding a CPC certification from the American Academy of Professional Coders (AAPC), Natalie is a seasoned professional actively managing medical billing, medical coding, verification, and authorization services at OSI.

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