Modifier 24
Unrelated evaluation and management service by the same physician during a postoperative period
Use it when
- An E/M during a global period addressing a condition unrelated to the surgery
- Treatment of a new problem arising during the postoperative window
- An unrelated chronic condition managed during a postoperative visit
Do not use it when
- Routine postoperative follow-up, which is included in the surgical payment
- Management of the expected postoperative course
- Complications related to the surgery, which have their own modifiers
A worked example
A patient is three weeks into the global period following a knee procedure. They attend for a scheduled postoperative check and, at the same visit, are evaluated for newly elevated blood pressure requiring medication adjustment.
The postoperative check is included in the surgical payment and is not billable. The hypertension evaluation is unrelated to the knee and is separately reportable with modifier 24.
The note has to establish the separation. A single narrative covering the knee and the blood pressure together supports one service, and it will be the one already paid for.
What decides it
Global periods run 10 or 90 days depending on the procedure, and knowing which applies is a prerequisite to using this modifier correctly. A service on day 45 following a 10-day global procedure needs no modifier at all.
The distinction between unrelated and complication matters, because they use different modifiers. An unrelated problem takes modifier 24. A complication requiring a return to the operating room takes a different one, and an unrelated procedure takes another again.
The diagnosis on the claim carries much of the weight. An E/M with modifier 24 reported under the same diagnosis as the surgery invites the obvious question, and the answer has to be in the note rather than in the modifier.
Denial codes this affects
Modifiers often confused with this one
Terms used here — E/M Coding · Modifier · Denial
How we handle it — Medical Coding · Denial Management · Claims Management
Every CPT and HCPCS modifier with a guide
Coverage attestation
Evaluation and management
Global period
- 24Unrelated E/M in a Global Period
- 57Decision for Surgery
- 78Unplanned Return to the Operating Room
- 79Unrelated Procedure in a Global Period
- 58Staged or Related Procedure
Multiple and bilateral
Primary sources
What the payers and code-set maintainers actually publish about modifier 24.
- Global Surgery booklet (opens in a new tab)
Centers for Medicare & Medicaid Services — What the 10 and 90-day global periods include, and which modifiers break out of them. The authority behind most postoperative bundling disputes.
- Medicare Claims Processing Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — The operative manual for how Medicare claims must be coded, submitted, adjusted and appealed. When a payer policy and a vendor's advice disagree, this settles it.
- 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 24
For an evaluation and management service during a surgical global period that is unrelated to the surgery — a new problem, or an unrelated chronic condition. Routine postoperative follow-up is included in the surgical payment and is not separately billable.
Modifier 24 covers an unrelated E/M service during the global period. Modifier 79 covers an unrelated procedure. Both say the service was unrelated to the original surgery; they differ in what kind of service is being reported.
Ten or ninety days depending on the procedure. Knowing which applies is a prerequisite — a service after the window has closed needs no global-period modifier at all.
It invites scrutiny. Reporting an unrelated service under the surgical diagnosis is internally contradictory, and the documentation has to establish the separation rather than the modifier asserting it.
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