What Is CPT Code 45380?
CPT code 45380 is the gastroenterology procedure code for a flexible colonoscopy in which the physician advances the scope past the splenic flexure and removes one or more tissue samples with biopsy forceps. It is billed once per session no matter how many biopsies are taken, and it replaces the base diagnostic colonoscopy code 45378 for that visit.
When 45380 replaces 45378. The moment any tissue is sampled. 45378 is the base diagnostic colonoscopy, and once a biopsy happens the session becomes 45380. You never bill both on the same claim.
The costliest error. A screening colonoscopy that converts to a biopsy without the right modifier. Medicare needs modifier PT and commercial payers need modifier 33, or the preventive benefit is lost and the claim denies.
One unit per session. No matter how many forceps biopsies are taken, 45380 is reported a single time, and the code carries a zero-day global period.
What CPT Code 45380 Covers
Two things must be true to report 45380. First, the colonoscope has to reach proximal to the splenic flexure. If the scope does not get that far, the service falls into the flexible sigmoidoscopy series, not the colonoscopy series. Second, at least one biopsy has to be taken with forceps. The number of samples does not change the code. One biopsy or ten, 45380 is reported a single time for the session, the medically unlikely edit allows one unit per date of service, and the code carries a zero-day global period, so there are no bundled postoperative days to track.
The rule sounds simple, yet 45380 is one of the most misbilled codes in gastroenterology, and the errors almost always trace back to three things: modifiers, screening conversions, and thin documentation. This guide works through each pressure point using the 2026 rules.
The Colonoscopy Code Hierarchy
Colonoscopy coding runs on a hierarchy, not a menu. 45378 is the base diagnostic exam. The moment the physician intervenes, the code upgrades to whatever describes the intervention, and the base code drops off the claim. The American Medical Association and the American Society for Gastrointestinal Endoscopy both frame it the same way: report only the single highest-level service performed in the session. This is the most-intensive-procedure rule, and it is where revenue leaks or gets clawed back.
| Code | Procedure | 2026 Work RVU |
| 45378 | Diagnostic colonoscopy, no intervention | 3.18 |
| 45380 | Colonoscopy with biopsy by forceps | 3.47 |
| 45385 | Removal of polyp by snare technique | 4.46 |
Related codes sit on the same ladder: 45384 covers removal by hot biopsy forceps, and 45388 covers ablation. The rule that matters most is this: never bill 45378 with 45380 for the same colonoscopy, and never bill 45380 with 45385 at the same lesion, because the higher therapeutic code already includes the diagnostic work. One 2026 wrinkle worth modeling: under the CMS CY 2026 Physician Fee Schedule final rule (CMS-1832-F), CMS applied an efficiency adjustment to work RVUs for non-time-based procedures, so the net value of a high-volume colonoscopy code can move even when the code descriptors do not change. Across the billing companies we vet, the strongest GI operators run that reimbursement-impact analysis against their own colonoscopy mix rather than assuming last year’s rates hold.
The Screening-to-Diagnostic Trap
This is where most 45380 dollars are won or lost. A patient books a preventive screening. During the exam the endoscopist sees something and biopsies it. The service just converted from preventive screening to diagnostic, and if the claim does not signal that it started as a screening, the patient gets billed as if they walked in for a diagnostic workup. For Medicare, append modifier PT. For commercial and Medicaid plans, append modifier 33 instead. Skip the modifier and the preventive benefit disappears, the patient is charged cost sharing they should not owe, and the claim becomes a denial or an appeal waiting to happen.
There is a cost-sharing wrinkle worth knowing so your front desk can counsel patients before the procedure. Under the Consolidated Appropriations Act 2021 phase-down, when a Medicare screening colonoscopy converts because a biopsy is taken or a polyp is found, the beneficiary is responsible for 15 percent coinsurance from 2023 through 2026, 10 percent from 2027 through 2029, and zero beginning in 2030. The Part B deductible is waived under the Affordable Care Act. The American College of Gastroenterology and the American Gastroenterological Association both publish this schedule, yet patients rarely know it, and the surprise bill usually lands on your practice as a phone call.
Diagnosis coding has to line up too. On the Medicare side, the screening itself is reported with G0121 for average-risk patients or G0105 for high-risk patients, while a true commercial screening pairs with Z12.11. Once the visit is diagnostic, the ICD-10 has to reflect the reason for the biopsy: rectal bleeding, chronic diarrhea, abdominal pain, anemia, or a history code such as Z85.038. Mismatched CPT and ICD-10 is a top denial driver on 45380 claims.
Losing 45380 claims to screening conversions and modifier errors? A billing partner that lives in GI codes catches these before the claim leaves the door. Get matched with vetted gastroenterology billing companies in about 30 minutes, at no cost.
Modifiers That Make or Break a 45380 Claim
Beyond PT and 33, a handful of modifiers show up on 45380 regularly. Getting them right is the difference between a first-pass payment and a rework queue.
- Modifier 59 or XS: use when 45380 is billed alongside 45385 for a biopsy and a snare polypectomy at separate, distinct lesions. At the same site, 45380 is bundled into 45385, so without a distinct-site modifier the biopsy line is denied. The note has to name both anatomical locations.
- Modifier 53: the colonoscopy was started but discontinued before the scope reached the cecum. This is not sigmoidoscopy. Report the planned colonoscopy code with modifier 53.
- Modifier 52: reduced service, for a partially completed procedure per payer guidance. See modifier 52 for how payers want it documented.
- Modifier 22: increased procedural services, reserved for genuinely complex cases with documentation to back it.
- Modifier 51: multiple procedures, subject to the multiple endoscopy payment reduction, under which Medicare pays the highest-valued endoscopy in full and reduces the others by the value of the shared base endoscopy.
Documentation Auditors Read
The operative note is the claim’s defense. For 45380, reviewers look for the extent of the exam, meaning the scope reached proximal to the splenic flexure and ideally the cecum, a clear indication and medical necessity, each biopsy site described, the instrument named as cold biopsy forceps, and how the specimens were handled and sent to pathology, which the lab bills separately under 88305. One recurring audit target we see flagged across GI practices is upcoding a forceps biopsy, which is 45380, to a snare polypectomy, which is 45385. If the note only describes forceps, the code is 45380, and a snare code will not survive review.
Common 45380 Denial Patterns
The Billing Service Quotes network has matched more than 2,000 provider practices with vetted billing companies, and the gastroenterology partners in that network flag the same 45380 failure points again and again. Screening-to-diagnostic conversions with a missing PT or 33 modifier top the list. Right behind them are distinct-site biopsy-plus-snare claims filed without modifier 59 or XS, and ICD-10 selections that do not support the reason for the biopsy. None of these are complex clinically. They are workflow gaps, and they are exactly what a specialty billing team catches on the front end instead of chasing on appeal.
That is the practical difference between a generalist billing service and one that works GI codes every day, including the professional and facility split when a colonoscopy is performed in an ambulatory endoscopy center. The practices that stop the bleed are rarely doing anything heroic. They simply have coders who know that a biopsy converts the session, that the modifier has to travel with it, and that the diagnosis code has to tell the same story. Matching through gastroenterology billing services is handled by a real person who understands the specialty, and connections happen in about 30 minutes, so a practice buried in 45380 denials is not waiting weeks for help.
Frequently Asked Questions
Stop rewriting the same 45380 appeals. Gastroenterology Billing matches your practice with vetted gastroenterology billing companies built for colonoscopy coding, across all 50 states, with rates starting as low as 2.95 percent and a match in about 30 minutes. Getting matched is free to providers.
Can you bill 45380 and 45385 together?
Only when the biopsy and the snare polypectomy are performed on separate, distinct lesions at different anatomical sites. Bill 45385 as the primary code and 45380 with modifier 59 for commercial or XS for Medicare, and document both sites. At the same lesion, 45380 is bundled into 45385.
Is 45380 covered as a screening?
Not on its own. 45380 is a diagnostic code. If the exam started as a preventive screening and a biopsy converted it, append modifier PT for Medicare or modifier 33 for commercial to preserve the screening benefit and the waived deductible.
How many units of 45380 can you bill per session?
One. Multiple forceps biopsy sites still report a single unit. The medically unlikely edit is one per date of service, and 45380 carries a zero-day global period, so there are no postoperative days bundled into the payment.
What does the patient owe if a screening becomes a 45380?
For Medicare, the Part B deductible is waived and coinsurance is 15 percent through 2026, then 10 percent for 2027 through 2029, and zero beginning 2030, under the Consolidated Appropriations Act phase-down. Commercial screening conversions billed with modifier 33 are generally covered without cost sharing.
What ICD-10 codes support 45380?
For a converted screening, the screening code plus the finding. For a diagnostic exam, the symptom or history driving the biopsy, such as rectal bleeding, abdominal pain, anemia, or Z85.038 for a personal history of colon cancer. The diagnosis has to justify the biopsy.
What is 45380 worth in 2026?
The 2026 work RVU is 3.47, above diagnostic colonoscopy at 3.18 and below snare polypectomy at 4.46. Actual payment varies by site of service, since facility settings pay a lower professional fee, and by geographic adjustment under the Medicare Physician Fee Schedule.
