Modifier 24: Unrelated Visits in the Postoperative Period
Modifier 24 gets an unrelated E/M visit paid during a surgery's global period. Medicare's rules, the diagnosis that proves it, and when 24 is the wrong choice.
Modifier 24 is a billing modifier added to an evaluation and management (E/M) code when the surgeon, or another practitioner in the same group and specialty, sees the patient during a procedure's postoperative period for something unrelated to that procedure. Without it, Medicare assumes the visit is routine follow-up care, which is already paid in the surgery's global fee, and denies it.
Key takeaways
- 24 goes on the E/M code, for visits after the day of surgery and inside the 10- or 90-day global period.
- The visit must be unrelated to the surgery. A diagnosis that clearly shows that is acceptable documentation.
- Complications that don't need a return to the operating room are part of the global package, so 24 doesn't apply.
- Same-day visits use 25 or 57; unrelated procedures in the global period use 79.
- 24 doesn't change the rate. The visit is paid at its normal fee schedule amount.
Modifier 24 · payment effect
With and without the modifier
99213 without 24 · national office
$95.19
Office visit
99213-24 · No change to the rate
$95.19
Lets an unrelated E/M during a post-op period be paid at its full rate instead of being bundled into the surgery.
What modifier 24 means
Procedures with a 10- or 90-day global period include the related follow-up care: postoperative visits, dressing changes, suture removal and treatment of complications that don't need another trip to the operating room. Medicare denies any E/M from the same surgeon during that window unless it's marked as outside the package.
Modifier 24 is that marker. CMS says a 24 visit must be "sufficiently documented to establish that the visit was unrelated to the surgery," and that "a diagnosis code that clearly indicates that the reason for the encounter was unrelated to the surgery is acceptable documentation" (Claims Processing Manual, Pub. 100-04, ch. 12, §40.2.A.7).
Global surgery period · 27447
Total knee replacement
90-day global period ends
May 31, 2026
Covers Mar 1, 2026 through May 31, 2026 (92 days, including the day before surgery).
Visit on Apr 1, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
When to use modifier 24
- A new, unrelated problem. Five weeks after a total knee replacement (27447), the orthopedist evaluates the patient's shoulder pain. Bill 99213-24 with the shoulder diagnosis.
- Treating the underlying condition, not the recovery. Ongoing management of the disease that led to surgery, beyond normal recovery, is outside the global package.
- Postoperative care by a different practitioner. A physician who accepted transfer of postoperative care and billed with modifier 55 also uses 24 for any unrelated visits.
Use the global period calculator to check whether the visit date falls inside the window at all. After the window ends, no modifier is needed.
CMS payment indicators · 27447
Total knee replacement
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 1 | Bilateral with modifier 50 pays 150% of the fee schedule amount. |
| Assistant at surgery (80/81/82/AS) | 2 | Paid. |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.10/0.69/0.21 | Share of the payment for pre-op, the procedure itself, and post-op care. |
When not to use modifier 24
Also don't use 24:
- On the day of surgery. A separate visit that day is modifier 25; a decision-for-surgery visit is 57.
- For a procedure. Unrelated procedures in the global period use 79; staged or planned ones use 58.
- For inpatient visits during the surgical stay unless you're also treating a separate condition. Care during the admission for the surgery is paid through the global fee.
- For unrelated critical care during the global period. CMS requires modifier FT on those critical care codes instead.
- When another practitioner of a different specialty sees the patient. Their visits aren't part of your global package, so no modifier is needed.
How modifier 24 affects payment
There's no payment adjustment: the E/M is paid at its full fee schedule amount. Without the modifier, Medicare denies the visit as part of the surgical package.
The global period itself is counted from the procedure date. Major surgeries (090) include the day before, the day of surgery and the 90 days after. Minor procedures (010) include the day of surgery and the 10 days after. Procedures with a 000 global include only the day of surgery, so a visit the next day needs no modifier.
Modifier 24 vs 25, 79 and 58
| Modifier | Goes on | Timing | Use it when |
|---|---|---|---|
| 24 | E/M | During the postoperative period | Visit is unrelated to the surgery |
| 25 | E/M | Same day as a procedure | Visit is significant and separate from the procedure |
| 79 | Procedure | During the postoperative period | Procedure is unrelated; starts its own global period |
| 58 | Procedure | During the postoperative period | Procedure was staged, more extensive, or therapy after a diagnostic surgery |
FAQ
What is a 24 modifier used for?
To get an E/M visit paid when it happens during a surgery's postoperative period but treats a problem unrelated to that surgery.
What is modifier 24 and 25?
Both go on E/M codes and both get a visit paid separately from surgery. 25 is for a separate visit on the same day as a procedure. 24 is for an unrelated visit on a later day inside the postoperative period.
What is the difference between modifier 24 and 79?
24 is for an unrelated visit (an E/M code) during the global period. 79 is for an unrelated procedure during the global period, and it starts a new global period for that procedure.
When should modifier 24 be used?
When the same surgeon or group sees the patient after the day of surgery, before the 10- or 90-day global period ends, for a reason the diagnosis shows is unrelated to the procedure.
Does Medicare need records with a modifier 24 claim?
Not usually. A diagnosis code that clearly shows the visit was unrelated is acceptable documentation. Keep a note that supports it, because contractors can request it.
Keep reading
- Global period calculator to find the end of any procedure's global window.
- Modifier 79 and modifier 58 for procedures in the postoperative period.
- Modifier 25 vs 59 for same-day visits and procedures.
- Codes on this page: 99213 99214 27447
Sources: Medicare Claims Processing Manual, Pub. 100-04, ch. 12, §30.6.6.A, §40.1 and §40.2.A.7; Noridian JE Part B, Modifier 24 (updated May 9, 2025). Verified October 6, 2026.
