Modifiers provide additional details about CPT codes submitted and the services rendered, without altering the procedure code’s definition. Modifiers 51 and 59 are used when multiple services are performed during a single encounter, each serving a distinct purpose. These modifiers are frequently applied in anesthesiology and general surgery medical billing and coding services.
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Modifier 51 Multiple procedures
Modifier 51 indicates that multiple procedures were performed at the same session. It applies to:
- Different procedures performed at the same session: An example of this would be if a surgeon performs both an excision of a malignant skin lesion and a biopsy of a separate lesion on the same patient during a single operative session; in this case, the biopsy code would be appended with Modifier 51 to indicate that it was performed as part of a multiple procedure session with the primary excision procedure
- A single procedure performed multiple times at different sites: A dermatologist performing a lesion removal on three separate areas of a patient’s skin would be considered a single procedure performed multiple times at different sites
- A single procedure performed multiple times at the same site: A surgeon removing multiple small skin lesions from the same area of the body during a single procedure would be considered a “single procedure performed multiple times at the same site”.
Using Modifier 51: Points to Note
- Modifier 51 is used only when two or more procedures are performed. It is not applicable when a procedure is performed along with an Evaluation and Management (E/M) service.
- There are situations where multiple procedures are performed but modifier 51 should not be used. It should not be appended to add-on CPT codes. A typical example of add-on code to which Modifier 51 should not be appended is 64462 Paravertebral block (PVB), (paraspinous block), thoracic; second and any additional injection site(s) (includes imaging guidance, when performed).
- Examples of other codes designated as Modifier 51 exempt in CPT’s Appendix E include:
31500 Intubation, endotracheal, emergency procedure
36620 Arterial catheterization or cannulation for sampling, monitoring or transfusion (separate procedure); percutaneous
93503 Insertion and placement of flow directed catheter (eg, Swan-Ganz) for monitoring purposes
99143: Moderate sedation services for patients under 5 years of age
99141: Conscious sedation with or without analgesia
99142: Conscious sedation that is oral, rectal, or intranasal
Modifier 51 affects reimbursement, as many payers apply a multiple procedure reduction to additional procedures reported after the primary one. To optimize payment, the American Society of Anesthesiologists recommends always listing the most complex procedure first on your claims and use Modifier 51 appropriately for any subsequent services when required.
Modifier 59 Distinct Procedural Service
This modifier is used to indicate that a procedure is separate and distinct from another procedure performed on the same date of service. It is typically applied to bypass National Correct Coding Initiative (NCCI) edits when procedures are performed at different anatomical sites, during separate patient encounters, or when they are not typically performed together. Indications for using Modifier 59 according to CPT guidelines are:
- Different session or encounter
- Different procedure or surgery
- Different site
- Separate incision, excision, lesion, injury, or body part
Modifier 59 is required when reporting or billing two services that are typically bundled together. CCI guidelines clarify, “Use of modifier 59 to indicate different procedures/surgeries does not require a different diagnosis for each HCPCS/CPT coded procedure/surgery. Additionally, different diagnoses are not adequate criteria for use of modifier 59. The HCPCS/CPT codes remain bundled unless the procedures/surgeries are performed at different anatomic sites or separate patient encounters.”
When using modifier 59 to break a CCI edit, the modifier should always be appended to the secondary (“column 2”) code.
Here are four examples of scenarios where Modifier 59 might be applied:
- Different Anatomical Sites
A dermatologist removes a premalignant lesion on the arm (CPT code 17000) and a benign lesion on the face (CPT code 17110). Modifier 59 is appended to one of the codes to indicate that the procedures were performed on different anatomical sites.
- Separate Incision or Treatment Area
A surgeon performs a meniscectomy (CPT code 29880) and a synovectomy (CPT code 29876) in different compartments of the same knee. Modifier 59 would be used to show that these are distinct procedures.
- Separate Encounter
A patient has an office (E/M) visit (CPT code 99213) in the morning and later returns to the clinic for an ECG (CPT code 93000). Modifier 59 is appended to the ECG code to indicate a separate encounter.
- Bundled Codes
Normally, 22845 Insertion of anterior spinal instrumentation is bundled with 22551 Cervical spinal fusion, anterior technique. If documentation warrants that the procedures were performed independently, Modifier 59 can be applied to 22845 to justify separate reimbursement.
CCI guidelines specify three conditions under which modifier 59 should always be used:
- When a diagnostic procedure precedes a surgical or non-surgical therapeutic procedure and is the basis on which the decision to perform the surgical or non-surgical therapeutic procedure is made.
- When a diagnostic procedure follows a surgical procedure or non-surgical therapeutic procedure.
- If two separate and distinct timed services are provided in separate and distinct time blocks, modifier 59 may be used to identify the services.
When Not to Use Modifier 59
- When a more appropriate modifier is available. For example, CPT states that modifier 91 Repeat clinical diagnostic laboratory test is preferable to modifier 59 when reporting repeat laboratory tests performed on the same day.
- On Evaluation and Management (E/M) codes.
- The procedures are performed simultaneously
- The narrative description of the two codes is different
- The diagnostic procedure is part of the therapeutic procedure
Understanding CPT codes and modifier usage is essential to ensure appropriate payment for your services.
The following table summarizes the applications of modifiers 51 and 59:
| Modifier 51: Multiple Procedures | Modifier 59: Distinct Procedural Service |
|---|---|
| additional procedure /same session | distinct procedure/different encounter |
| same procedure/multiple times | distinct procedure/different provider |
| same procedure/different site | distinct procedure/different site |
| do not append to add-on CPT codes | do not use if another modifier is applicable |
Being familiar with local carriers’ requirements and ensuring proper documentation of your services is essential to prevent billing issues and claim denials. Partnering with a knowledgeable medical billing company can help ensure accurate and compliant modifier usage.
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