CPT Modifier 77
Repeat Procedure by Another Physician or Other Qualified Health Care Professional
Source: AMA CPT / CMS HCPCS Level II definitions. Maintained by the D3rx Clinical Billing Team.
What modifier 77 means
Modifier 77 indicates a procedure or service was repeated by a different provider after the original. It distinguishes a clinically necessary repeat performed by another clinician from a duplicate claim so the second occurrence is paid appropriately.
When to use it
A different physician repeats the same test or procedure (often the same day) — for example, a second radiologist re-performs and re-interprets a study, or a covering physician repeats a procedure.
Documentation checklist
The record should support every item below before you append modifier 77.
- That a different provider performed the repeat service
- The clinical reason the repeat was necessary
- Details linking it to the original service
Do NOT use modifier 77 when
- The same provider repeated the service — use modifier 76
- The line is a true duplicate
- The repeat is a staged/related procedure during a global period — use 58 or 78
Common denial reasons
- Denied as a duplicate when 77 was omitted
- Medical necessity for a second provider's repeat not documented
- Frequency limits exceeded
How to appeal a modifier 77 denial
Submit documentation showing a different rendering provider and the medical reason the repeat was required (e.g., independent re-read or a repeat study after a change in condition). Distinguish it clearly from a duplicate to clear the edit.
Payer notes
Modifiers 76 and 77 both override duplicate edits; 77 specifically signals a different provider. Payers commonly request documentation explaining why the repeat by another clinician was necessary.
Related & commonly confused modifiers
Where modifier 77 is used
- Radiology
- Diagnostic testing
- EKG and cardiac monitoring
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Medical billing disclaimer
Modifier definitions follow standard AMA CPT and CMS HCPCS Level II guidance and are for educational reference. Payer policies, billing formats, and coverage rules vary and change. Always verify the current rule with the specific payer before submitting. D3rx is not responsible for claim outcomes.