Modifier 77
Repeat procedure or service by another physician
Use it when
- The same procedure repeated the same day by a different physician
- A second reading or study performed by another clinician after a change in condition
- Cross-coverage situations where a covering physician repeats a service
Do not use it when
- The repeat was by the same physician, which takes modifier 76
- A repeat clinical diagnostic laboratory test, which takes modifier 91
- Two distinct services rather than a repeat of the same one
A worked example
A study is performed and interpreted in the morning. The patient's condition changes and the study is repeated in the evening, interpreted by the physician then on duty.
Both interpretations were genuinely performed by different clinicians. Modifier 77 on the second distinguishes it from a duplicate of the first, which is how it would otherwise adjudicate.
The second report must stand alone with its own indication and findings. Two claims supported by one report is not a repeat by another physician — it is a duplicate.
What decides it
The choice between modifiers 76 and 77 is factual rather than strategic: it depends entirely on whether the same clinician repeated the service. Using the wrong one misstates who performed the work.
Cross-coverage and shift-based settings generate most legitimate uses of 77, which means emergency departments, hospitalist services and radiology groups see it far more than scheduled outpatient practices.
As with modifier 76, the repeat needs a clinical reason. A study repeated because the first was technically inadequate is generally not separately payable, whoever performed it.
Denial codes this affects
Modifiers often confused with this one
Terms used here — Modifier · Rejection · NPI
How we handle it — Claims Management · Medical Coding · Denial Management
Every CPT and HCPCS modifier with a guide
Coverage attestation
Evaluation and management
Global period
Multiple and bilateral
Repeat
- 76Repeat Procedure, Same Physician
- 91Repeat Clinical Diagnostic Lab Test
- 77Repeat Procedure, Another Physician
Primary sources
What the payers and code-set maintainers actually publish about modifier 77.
- NCCI Policy Manual for Medicare Services (opens in a new tab)
Centers for Medicare & Medicaid Services — The reasoning behind the edits, chapter by chapter. Where the edit files tell you two codes conflict, this explains why — which is what an appeal has to address.
- Medically Unlikely Edits (MUE) tables (opens in a new tab)
Centers for Medicare & Medicaid Services — The maximum units of a code payable for one patient on one day. Unit-based denials usually trace to this table rather than to a coding error.
- CPT code set (opens in a new tab)
American Medical Association — Maintainer of CPT. Annual changes to CPT are the most common cause of a sudden, unexplained rise in denials each January.
Questions about modifier 77
When the same procedure is repeated on the same day by a different physician than the one who performed it originally. Without it the second claim adjudicates as a duplicate, since the code, date and often the billing entity are identical.
The identity of the repeating clinician. Modifier 76 is a repeat by the same physician; 77 is a repeat by a different one. The choice is factual, and using the wrong one misstates who performed the work.
Cross-coverage and shift-based settings — emergency departments, hospitalist services and radiology groups — where a different clinician is genuinely on duty when a repeat becomes necessary.
Generally not. A study repeated because the first was technically inadequate is not separately payable regardless of who performed the repeat. The repeat needs a clinical reason, documented.
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