Modifier 58: Staged or Related Procedure in the Global Period
Modifier 58 tells Medicare that a second procedure by the same surgeon, inside the global period of the first, was planned, more extensive, or therapy after a diagnostic procedure. It earns separate payment and starts a new global period.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: modifier 58 covers a planned, more extensive or follow-up therapeutic procedure during the global period of the first one. It is not for treating a complication that sends the patient back to the operating room, which is modifier 78.
What Does Modifier 58 Mean?
Modifier 58 is a CPT modifier for a staged or related procedure or service by the same physician during the postoperative period of an earlier procedure. Chapter 12, section 40.2 A 6, of the Medicare Claims Processing Manual says it was created to make staged or related surgical billing possible, and that it is not used for a problem that needs a return to the operating room.
The manual lists three reasons for it. The second procedure was planned prospectively or at the time of the first, it was more extensive than the first, or it was therapy following a diagnostic surgical procedure.
Which Three Situations Qualify for Modifier 58?
| Situation | What the record has to show |
|---|---|
| Planned from the start | The staging was decided before or at the first procedure. Section 40.1 B says the decision to stage is made prospectively or at the time of the first procedure. |
| More extensive | The second procedure goes further than the first, for example after a smaller attempt did not do the job. |
| Therapy after a diagnostic procedure | The first procedure was diagnostic and the second treats what it found. |
The 2026 NCCI Policy Manual adds a case. When a diagnostic endoscopy leads to the decision for an open procedure, both can be reported with 58 on the open procedure. An endoscopy done only to check landmarks or the extent of disease is not separately reportable.
What Is the Difference Between Modifier 58 and Modifier 78?
Modifier 58 is for planned or progressive work. Modifier 78 is for an unplanned return to the operating room to deal with a related problem. The manual states that 58 is not used to report treatment of a problem that requires a return to the operating room.
| Question | 58 | 78 |
|---|---|---|
| Planned or expected at the first operation? | Yes, or more extensive, or therapy after diagnosis | No, the return is unplanned |
| Treating a complication that needs the OR? | No | Yes, though CPT does not limit 78 to complications |
| Code billed | The second procedure's own code | The code for the return-trip procedure, not the original, unless the identical procedure is repeated |
| Payment | Separate payment allowed | Intra-operative share of the fee |
What Happens to the Global Period?
A new postoperative period begins when the next procedure in the staged series is billed, according to section 40.2 A 6. The earlier period does not simply continue. If the second procedure lands inside the first global period without 58, 78 or 79, section 40.4 A tells the MAC to deny it.
Codes with an XXX global indicator in the fee schedule are outside the global concept and can be paid separately without a modifier. See global surgery periods for how the days are counted.
How Does It Sit on the Claim?
Put 58 on the second procedure's line in box 24D of the CMS-1500, with its own date of service. The first procedure is already on file and is not re-billed.
A surgeon explores the abdomen to find the cause of a mass. Pathology confirms disease, and the surgeon returns two weeks later to remove the affected bowel as planned therapy.
How Does Modifier 58 Read on the Form and on the Remittance?
Modifier 58 goes on the second procedure's line in item 24D, with its own date of service.
Without 58 the second procedure meets the section 40.4 messages, shown as CO with CARC 97 or B15. Read the staged line separately from the first procedure, which is already paid.
A planned second-stage procedure returns CO-97 for $410.00.
What Edits and Denials Apply?
The NCCI manual says 58 bypasses PTP edits that allow a modifier, and the claims manual excludes services billed with 58 from the global surgery prepayment audit. Without it, the second procedure meets the denial messages in section 40.4 D, group code CO.
| Code | X12 description | Usual cause here |
|---|---|---|
| CO-97 | The benefit for this service is included in the payment or allowance for another service already adjudicated. | The staged procedure was billed inside the first global period without 58. |
| CO-B15 | The service requires that a qualifying service be received and covered, and that service has not been adjudicated. | The second stage reached the payer before the first. |
Compare modifier 57 for the decision visit and modifier 79 for an unrelated procedure. Our billing and coding audits look at staged cases across a group. If these denials keep coming back, our denial management team can work them.
Related Codes
- Medicare Claims Processing Manual, chapter 12, sections 40 to 40.4 · CMS
- Medicare NCCI Policy Manual 2026, all chapters (revision date 1/1/2026) · CMS
- MLN907166: Global Surgery (December 2025) · CMS Medicare Learning Network
- Physician Fee Schedule relative value files, RVU26D (October 2026) · CMS
- Claim Adjustment Reason Codes · X12
- Medicare Claims Processing Manual, chapter 26 (CMS-1500 items) · CMS
- Medicare Claims Processing Manual, chapter 22, sections 60.1 to 60.3 (group codes, CARC, RARC on the remittance) · CMS
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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 58 and modifier 78?
Modifier 58 is for planned, more extensive or follow-up therapeutic work in the global period. Modifier 78 is for an unplanned return to the operating room for a related procedure. The Medicare manual says 58 is not used for a problem that requires a return to the operating room.
02Does modifier 58 start a new global period?
Yes. Section 40.2 A 6 of the claims manual says a new postoperative period begins when the next procedure in the series is billed. The first period does not extend to cover it, so the second surgery carries its own pre- and postoperative days.
03Can modifier 58 be used with a diagnostic endoscopy?
Yes, in one case. The NCCI manual says that when a diagnostic endoscopy results in the decision to do an open procedure, both may be reported with 58 on the open procedure. An endoscopy only to assess landmarks or extent of disease is not separately reportable.
04Can 58 go on a procedure the surgeon decided to stage at the first operation?
Yes. The claims manual lists a procedure planned prospectively or at the time of the original procedure as a reason for 58. Procedures done in two or more parts, where the staging was decided up front, are listed as outside the original package.
05What if I bill the second procedure without a modifier?
Medicare contractors are told not to pay an additional procedure during the postoperative period of a prior procedure when it is billed without 58, 78 or 79. Expect a CO denial such as CARC 97 or B15, and correct the claim if the facts support 58.
Second-Stage Procedures Denying?
We check whether the case is staged, related or unrelated before the claim goes out.