What is the difference between modifier 76 and 77?
Modifier 76 marks a repeat of the same procedure by the same physician or qualified health care professional on the same date, and modifier 77 marks a repeat by a different one. Neither opens an NCCI edit, so both work only when the second performance is the same code, in a separate session, with a documented reason.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · 
In short: the person who performed the second procedure picks the modifier, not the person who ordered it. Only the repeat line carries it, and a repeat that is really a different code, a quality redo or a repeat lab test belongs under another rule.
How do you pick between 76 and 77?
Ask three questions about the second performance, in this order. If any answer is no, neither modifier fits. The modifier 76 page and the modifier 77 page define each one, and this post is the claim-side sequence.
- Is the code on both lines exactly the same procedure? Chapter 4 of the Medicare Claims Processing Manual says it is listed once, then listed again with the modifier.
- Was the second one a separate operative session or separate encounter on the same day? Hospital outpatient claims generally span one calendar day, so that is where 76 and 77 do their work.
- Who performed the second one? The same physician or qualified professional takes 76. Another one takes 77.
Chapter 4 also settles the confusing case. If it is unclear who ordered the second procedure, or whether the same provider ordered it, the choice depends only on whether the clinician who performed it is the same person. The performing clinician decides, so the second line should match that clinician's own note and NPI.
What do 76 and 77 claims look like in practice?
Serial ECGs in an emergency department show both cases. The first tracing is billed plain. The later one carries the modifier. The times in the chart are what separate it from a duplicate.
A patient has an ECG at 08:10. Chest pain returns at 14:40 and a second tracing is taken, with the new symptoms and the reason written in the note.
A facility claim follows the same logic with the repeat code and modifier in form locator 44 of the UB-04. The NCCI medicine chapter gives a facility case: inhalation treatment code 94640 is reported once per episode of care, and if the patient leaves and returns for a second episode with another treatment the same date, the second can be reported with 76.
A patient has a breathing treatment in the morning and leaves. The patient returns that evening and gets another.
Add the modifier only to the second line, and give each line its own unit count. Do not put 76 on both lines, because the first performance is not a repeat.
Which repeats are not 76 or 77?
| Situation | Right answer | Source |
|---|---|---|
| Diagnostic angiogram repeated on the day of an intervention, to define the anatomy | Modifier 59 or XU, plus 52 if only a portion is repeated | NCCI manual chapters V and IX |
| Image redone in the same radiology encounter for poor quality or more views | One unit of the appropriate code. No second line | NCCI manual chapter IX |
| A lab test repeated the same day for a clinical reason | Modifier 91, or 59, not 76. See modifier 91 and repeat lab tests | Claims Processing Manual ch. 16, 100.5.1 |
| The same code on the other side of the body | An anatomic modifier or 50. See bilateral procedures with modifier 50 | Claims Processing Manual ch. 12, 40.7 |
| Two different procedures by two clinicians | Each code on its own line, no 76 or 77 | NCCI manual chapter I |
The angiogram row matters in a cath lab. A second angiogram on the same date as the intervention needs the 59 or XU route and a clinical reason to repeat the study, not 76.
Do 76 and 77 get past NCCI and MUE edits?
No on procedure-to-procedure edits. The NCCI manual says modifiers 22, 76 and 77 are not PTP-associated modifiers, so using them does not bypass a PTP edit. If a different pair of codes is colliding, you need a modifier on the bypass list, and the NCCI edits page explains the indicator.
On units it depends on the MAI. An MAI of 1 is a claim line edit, and the manual says 76, 77, 91 and the other listed modifiers may report the same code on separate lines, each judged against the MUE on its own. An MAI of 2 or 3 is a date of service edit that adds up the units on every line for that code and date, so splitting the units across two lines does not avoid it.
Which denials follow, and how do you fix them?
| Remit shows | First check | Fix |
|---|---|---|
| CARC 18, exact duplicate | Did the repeat line carry 76 or 77? | If the session was separate and charted, add the modifier to the second line and send a corrected claim |
| CARC 97, included in another service | Was the second performance a continuation of the first? | If it was, the denial stands. If not, correct the claim with the modifier and the note |
| CARC 4, inconsistent with the modifier | Is the modifier on the first line, or on a code that was not repeated? | Move it to the repeat line only |
| CARC 151, frequency not supported | Does the note give a clinical reason for the second one? | Appeal with the time-stamped note and the order |
Keep the second note specific: the time, the new symptom or result that prompted the repeat, and who performed it.
How Nucleus Align handles it
Our medical coding team includes AAPC and AHIMA certified coders, and we work denials within 48 hours. Repeat services are checked against the time-stamped chart before the claim is sent, a routine that fits cardiology billing. Book a call to review your repeat-service denials, or read more on the blog.
- Medicare Claims Processing Manual, chapter 4, section 20.6.5 · CMS
- NCCI Policy Manual for Medicare Services, 2026 (chapters I, V, IX, XI) · CMS
- Medicare Claims Processing Manual, chapter 16, section 100.5.1 · CMS
- Medicare Claims Processing Manual, chapter 12, section 40.7 · CMS
- Claim adjustment reason codes · X12
We check every rule, code and deadline against the official source. See our editorial policy.
Common questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01What is the difference between modifier 76 and 77?
Modifier 76 reports that the same physician or qualified health care professional repeated a procedure on the same date. Modifier 77 reports that another one repeated it. In both cases the code is identical and the second performance happened in a separate session or encounter. The performing clinician decides, not the person who ordered.
02Do modifiers 76 and 77 bypass NCCI edits?
No. The NCCI Policy Manual says modifiers 22, 76 and 77 are not PTP-associated modifiers, so they do not bypass a procedure-to-procedure edit. They can only report the same code on separate lines when the MUE is a claim line edit with an adjudication indicator of 1.
03Do I put modifier 76 on both procedure lines?
No. The first performance is billed without a modifier and only the repeat carries 76 or 77. Chapter 4 of the Medicare Claims Processing Manual says the procedure is listed once and then listed again with the appropriate modifier. Each line has its own units.
04Is a repeat lab test billed with modifier 76?
No. Medicare uses modifier 91 or 59 for a laboratory test repeated on the same day when it is necessary to obtain multiple results in the course of treatment. Modifier 91 applies to tests paid under the clinical laboratory fee schedule. Do not use 76 for a repeat lab result.
Talk to a billing lead.
A 20-minute call about your payers, volume and setup. Monday to Friday, 9am to 5pm Eastern.