CPT 45378: Colonoscopy, diagnostic
What this code means, what it should cost, and how to dispute an overcharge.
Fair Price Reference
What is CPT 45378?
A diagnostic colonoscopy — visual examination of the colon. Preventive screening colonoscopies are free under the ACA; diagnostic colonoscopies can be billed to your deductible.
Typical setting: Surgery center or hospital endoscopy suite.
What CPT 45378 should cost
The Centers for Medicare & Medicaid Services (CMS) pays approximately $398 for CPT 45378 under the 2025 Physician Fee Schedule. This is what the federal government has determined is a reasonable payment for this service.
Private insurance typically pays 1.2–1.8x Medicare rates ($478–$716). Hospital chargemaster prices for CPT 45378 often range from $800 to $4000 — a markup of 2x to 10.1x over Medicare.
Common overcharges on CPT 45378
If a screening colonoscopy finds a polyp and becomes 'diagnostic,' the coding rules require modifier PT — without it, you could be billed thousands when the ACA guarantees it free. Dispute any charge for a screening colonoscopy where a polyp was found and removed.
About Gastroenterology billing
Medical procedures like this one are frequently overcharged on hospital bills. Comparing your charge against Medicare allowable and requesting an itemized bill are the first steps to identifying errors.
Request your itemized bill, compare charges against Medicare allowable, and dispute any charges exceeding 150% of the Medicare rate.
How to dispute a CPT 45378 overcharge
- Request the itemized bill. You are entitled to a detailed line-by-line bill showing every CPT code billed. Ask in writing.
- Compare to Medicare allowable. If the charge exceeds 150% of Medicare ($597), you have grounds to dispute.
- Request documentation. For E&M codes, ask for the visit note. For procedures, ask for the operative report. The documentation must justify the code billed.
- Send a formal dispute letter. Cite the specific discrepancy between the documentation and the code. Reference Medicare rates and NCCI edits where applicable.
- Follow up in writing. Give the provider 30 days to respond. If they don't, escalate to the state attorney general and insurance commissioner.
Got CPT 45378 on your bill?
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