CPT
43239 — Upper GI endoscopy with biopsy
High-volume procedure with predictable surprise-bill risk.
Gastroenterology
45378 — Diagnostic colonoscopy
Diagnostic (vs. screening) colonoscopy. Coverage rules differ significantly.
- Typical setting: Outpatient surgical center or hospital
- National avg charge (illustrative): Insurance allowed $700-$2,000 + facility $1,500-$5,000+ + anesthesia $400-$1,200.
- Most-disputed reason: Diagnostic vs screening coding causing unexpected cost-share.
What it means
What 45378 actually means
CPT 45378 is a diagnostic colonoscopy — performed because of symptoms, prior findings, or follow-up. It's distinct from a screening colonoscopy (G0121 / G0105) which has different coverage under ACA.
Federal rules now require that if a screening colonoscopy becomes diagnostic mid-procedure (because a polyp was found and removed), the patient still pays the screening cost-share — not the diagnostic cost-share. Many practices still bill it wrong.
Common errors with this code
What goes wrong on real bills.
Most bills that look correct still contain at least one of these issues. Up to 49% of medical bills contain errors (CFPB).
- Screening coded as diagnostic when polypectomy occurred mid-procedure (federal rule violation).
- Out-of-network anesthesiologist balance billing despite in-network facility.
- Pathology charges out-of-network without disclosure.
If you see 45378 on your bill
Three steps before paying.
1. Get the itemized bill. If your statement only shows a summary, request the CPT-level itemized bill before paying. Generate the request language →
2. Cross-check against the EOB. Compare what your insurer's Explanation of Benefits says you owe versus what the hospital is asking. They disagree more often than people think. Read the bill-vs-EOB guide →
3. Run a free Bill Scan. Upload the bill (and EOB if you have it) and BillBusted will flag the most likely issues with this specific code in your specific state. Run free scan →
Related codes
Other codes in this category.
People who land on 45378 often also see these adjacent codes on the same bill.
CPT
43644 — Laparoscopic Roux-en-Y gastric bypass with small intestine reconstruction
Verify the code matches the actual service and dose.
CPT
45380 — Colonoscopy, flexible, with biopsy, single or multiple
Verify the code matches the actual service and dose.
CPT
45385 — Colonoscopy, flexible, with removal of tumor/polyp/lesion by snare technique
Verify the code matches the actual service and dose.
Related BillBusted guides
Plain-English reads if you see 45378 on a bill.
45378 FAQ
Plain-English answers.
Why did my 'free' screening colonoscopy generate a $1,500 bill?
Most likely: a polyp was found and removed, and the practice billed the procedure as diagnostic instead of screening. Federal rules require the patient to be charged the screening cost-share even if the procedure became diagnostic. Dispute with this language.
Don't pay 45378 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.