Modifier 24: An Unrelated E/M Visit During a Surgical Global Period
Modifier 24 marks an E/M visit during a surgical global period (10 or 90 days) as unrelated to the surgery, so it pays instead of bundling into the global package. It goes on the E/M code, requires a diagnosis unrelated to the operation, and the same surgeon or group must be billing it.
- Applies to
- E/M codes billed by the operating provider/group during a 10- or 90-day global
- Payment impact
- Unlocks full E/M payment that would otherwise bundle into the surgical fee
- Audit risk
- Moderate — payers match the visit diagnosis against the surgical diagnosis
- Common denial
- CO-97 (payment included in the global allowance) when missing or unsupported
What does modifier 24 do?
It tells the payer that an E/M visit falling inside a surgical global period has nothing to do with the surgery, so it should pay separately instead of being absorbed into the surgical fee. The global package already includes all routine postoperative E/M by the surgeon for 10 or 90 days, which is why any visit you bill in that window without modifier 24 comes back CO-97.
It pairs with a family of global-period modifiers: 24 for unrelated visits, 79 for unrelated procedures, and 78 for unplanned returns to the OR.
When do you use it?
When the operating provider (or a partner in the same group and specialty) sees the patient during the global window for a genuinely separate problem. Realistic example: an orthopedic surgeon performs a total knee replacement (27447, 90-day global) on March 3. On April 10 the same patient comes in with acute gout in the opposite foot. Bill 99213-24 with the gout diagnosis — it pays in full. Without the modifier, the MAC assumes it is routine post-op care and denies it.
- New, unrelated illness or injury during the global window.
- Management of a chronic condition (diabetes, hypertension) the surgeon also handles, clearly separate from surgical recovery.
- Evaluation of a problem on a different body site or organ system.
When is it wrong or a denial trigger?
- Same diagnosis as the surgery. Claim systems auto-compare; matching diagnoses sink the claim.
- Complication management in the office. Under Medicare rules, treating complications that do not require a return to the OR stays inside the global package — modifier 24 does not rescue it.
- Routine recovery visits relabeled as "pain management" to squeeze out an E/M.
What are the documentation and payment impacts?
Payment is the full allowed amount of the E/M — for a 99213 that is roughly 1.3 work RVUs' worth of revenue you otherwise forfeit (check exact dollars with the Medicare fee calculator). Documentation must stand alone: a chief complaint and assessment that never mention the surgery, a distinct diagnosis pointer on the claim, and ideally a note stating the problem is unrelated to the recent procedure. If a payer denies a clean modifier 24 claim, appeal with the op note and the visit note side by side; these overturn frequently.
Frequently asked questions
Effectively yes. Medicare instructs that the visit must be for a condition unrelated to the procedure, and claim systems compare diagnoses. A visit coded with the same diagnosis as the surgery will almost always deny, even with modifier 24 attached.
No. Routine postoperative care — wound checks, dressing changes, suture removal, normal healing concerns — is part of the global surgical package. Modifier 24 on those visits is misuse and a refund risk if paid.
Bill the E/M with modifier 24, and if the decision for a new major surgery happens at that visit, add modifier 57 as well. The new procedure itself takes modifier 79 if it is unrelated to the original operation.
No. Providers outside the surgeon's group billing under a different TIN are not inside the global package, so they bill E/M normally. Modifier 24 exists only for the operating provider and same-group, same-specialty partners.
Sources & further reading
Reviewed by the ImmediCare Solutions RCM team
Certified billers and coders handling claims across 50+ specialties nationwide. This entry is reviewed against current payer policy and CMS rules. Last review: Jul 5, 2026.
Stop losing revenue to problems like this.
A free billing audit shows exactly where your practice is leaking money — no cost, no commitment.
