MLN: High-Frequency Medicare Modifier Reference
Reference to the modifiers most commonly used in Medicare professional billing: 25, 26, 50, 51, 57, 58, 59, 76, 77, 78, 79, 80, 82, and the X{EPSU} series.
Primary source
CMS Medicare Claims Processing Manual Ch. 12 (Modifier Use) →https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c12.pdf
Verified May 23, 2026 · This is the authoritative regulator URL. The summary below is a research aid; the linked source controls.
The Medicare Claims Processing Manual Chapter 12 is the authoritative reference for modifier policy. High-frequency modifiers in Medicare professional billing:
- 24: unrelated E/M during postoperative period (different diagnosis from surgery).
- 25: significant, separately identifiable E/M on same day as procedure.
- 26: professional component of a diagnostic service split into TC and PC.
- 50: bilateral procedure (single line, units 1).
- 51: multiple procedures (largely informational; many MACs do not require).
- 57: decision for major (90-day) surgery.
- 58: staged or related procedure during the global period.
- 59: distinct procedural service (generic NCCI override).
- 76: repeat procedure by same physician same day.
- 77: repeat procedure by another physician same day.
- 78: unplanned return to OR for related procedure during global.
- 79: unrelated procedure during postoperative period.
- 80, 81, 82: assistant surgeon (different employment contexts).
- GA, GZ, GY: ABN/coverage notification status.
- GT, 95: telehealth synchronous audio/video.
- TC: technical component.
- XE, XS, XP, XU: X{EPSU} subset of modifier 59 (more specific distinct-service modifiers).
Modifier 25, 26, 59, and 78/79 are the most frequently audited. Modifier documentation discipline is the practical defense.
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Related regulations
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Related across the archive
- RegulationModifier 25: Significant, Separately Identifiable E/M ServiceModifier 25 is appended to an E/M code when the E/M is significant and separately identifiable from another procedure or service performed on the same day by the same provider.
- RegulationNCCI Global Surgical Package PolicyMedicare's global surgical package bundles preoperative, intraoperative, and routine postoperative care into a single payment for the surgical CPT code, with global periods of 0, 10, or 90 days.
- RegulationNCCI Modifier Overrides (Modifier 59 and X{EPSU})Modifier 59 (and its more specific subsets XE, XS, XP, XU) is the principal mechanism for overriding a PTP edit when a procedure is distinct or independent from another performed on the same day.
- RegulationMLN: Split (or Shared) E/M VisitsReference to the Medicare rules for E/M services furnished jointly by a physician and an NPP in a facility setting, with the substantive-portion rule determining who reports.
- RegulationNCCI Bilateral Procedure Reporting RulesMedicare's policy for reporting bilateral procedures uses the MPFS Bilateral Indicator (0, 1, 2, 3, 9) and depends on whether the code descriptor already includes both sides.
- GlossaryModifier General ReferenceCatch-all reference for the wide CPT and HCPCS modifier set used in physician and outpatient billing.
- RegulationMLN: Advance Beneficiary Notice of Noncoverage (ABN, CMS-R-131)Reference to Medicare's ABN form required before furnishing items or services Medicare may not cover, shifting financial responsibility to the beneficiary.
- RegulationMLN: 2021 E/M Office Visit Coding RevisionsReference to the 2021 CPT E/M office visit (99202-99215) code revisions: history and exam no longer used for code selection; medical decision making or time controls.
Last reviewed May 23, 2026 · Citation verified May 23, 2026
Research aid, not legal advice. This summary is an administrative research aid prepared by D3rx. It does not certify compliance, provide legal advice, replace counsel, or guarantee an audit outcome. For authoritative regulatory text follow the primary source link at the top of this page. The practice remains responsible for reviewing, adopting, and maintaining its compliance program.