A colonoscopy is one of the most common outpatient procedures in the United States, and one of the most aggressively overbilled on hospital bills. The Medicare-set rate for CPT 45378 (diagnostic colonoscopy) is roughly $169 to $630 depending on the setting. Hospitals routinely bill anywhere from $1,500 to $8,500 for the same code. That gap is not an accident. It is a systematic markup that most patients never question because they never know the Medicare benchmark exists.
Quick Answer: The 2026 Medicare rate for a diagnostic colonoscopy (CPT 45378) is approximately $169 in a physician office setting and up to $630 as a facility-billed outpatient service. Hospital chargemaster prices for the same procedure average $2,100 to $6,200 before insurance adjustments. Screening colonoscopies under Medicare are free, no deductible, no coinsurance.
If you received a colonoscopy bill that looks nothing like these numbers, upload it to the CoveredUSA Bill Analyzer. It compares every line on your bill to the Medicare-set rate for that CPT code and flags charges that are statistically above the expected range.
What Is CPT 45378?
CPT code 45378 is the Current Procedural Terminology (CPT) code for a diagnostic colonoscopy, a procedure where a physician uses a flexible scope to visualize the entire colon through the rectum. The code is assigned by the American Medical Association and is the billing anchor for this procedure across all payers in the United States.
Related colonoscopy codes include:
| CPT Code | Description |
|---|
| 45378 | Diagnostic colonoscopy, no biopsy or removal |
| 45380 | Colonoscopy with biopsy |
| 45385 | Colonoscopy with snare polypectomy |
| G0105 | Screening colonoscopy, high-risk patient (Medicare) |
| G0121 | Screening colonoscopy, average-risk patient (Medicare) |
The distinction between CPT 45378 and the G-codes matters enormously for cost. If a screening colonoscopy is billed as diagnostic 45378 instead of G0105 or G0121, Medicare denies the claim or shifts the cost-sharing to the patient. This is one of the most common and costly billing errors on colonoscopy statements.
2026 Medicare Rate for CPT 45378
Medicare establishes a national fee schedule for every CPT code. For 2026, the physician fee schedule uses a conversion factor of $33.4209 per Relative Value Unit (RVU), per CMS.gov. The work RVU for CPT 45378 is 3.36, placing the physician reimbursement component at roughly $112 before practice expense and malpractice RVUs are added.
The all-in Medicare allowed amount varies by setting:
| Setting | 2026 Medicare Allowed Amount (Approx.) |
|---|
| Physician office (non-facility) | ~$169 |
| Ambulatory Surgery Center (ASC) | ~$440 to $520 |
| Hospital outpatient department | ~$500 to $630 |
Source: CMS Physician Fee Schedule, PayerPrice CPT 45378 data
These numbers represent what Medicare will actually pay. The "Medicare approved amount" is the ceiling. The provider cannot bill a Medicare patient more than this for covered services.
What Private Insurers Pay for CPT 45378
Private insurance pays more than Medicare but still far less than chargemaster prices. Based on 2026 claims data aggregated by PayerPrice:
| Payer | Average Reimbursement (CPT 45378) |
|---|
| Medicare | ~$169 (non-facility) |
| Blue Cross Blue Shield / Anthem | ~$442 |
| Aetna | ~$522 |
| UnitedHealthcare | ~$472 |
| Cigna | ~$570 |
Private payers negotiate rates that average roughly 254% of Medicare rates, per hospital pricing research published in PMC / NCBI.
What Hospitals Actually Charge: The Chargemaster Gap
Hospitals set their own list prices in documents called chargemasters. These prices are not what Medicare or insurers pay. They are starting points for negotiation. Uninsured and self-pay patients often get billed chargemaster rates with no automatic reduction.
For a colonoscopy procedure in 2026:
| Scenario | Typical Total Cost Range |
|---|
| Hospital outpatient chargemaster (list price) | $2,100 to $8,500 |
| Hospital outpatient, with insurance adjustment | $883 to $2,373 median |
| Ambulatory Surgery Center (ASC) | $650 to $1,800 |
| Self-pay cash price (ASC or independent) | $1,250 to $2,800 |
| Medicare approved total (physician + facility) | $500 to $630 |
Source: Taven Health 2026 Colonoscopy Guide, ASPE/HHS colonoscopy cost data
The national median facility cost for a diagnostic colonoscopy is approximately $1,475, per ASPE/HHS data. But the physician fee, anesthesia fee, and pathology charges (if biopsies are taken) stack on top. Total out-of-pocket costs including all components frequently land between $1,500 and $4,500 for insured patients after their plan's discounts.
The charge-to-Medicare-rate ratio for colonoscopy can exceed 10x at some hospital systems. That ratio is not random. Hospitals set high chargemaster prices knowing that insurers negotiate down and uninsured patients rarely appeal.
Medicare Colonoscopy Coverage: Screening vs. Diagnostic in 2026
Medicare's coverage rules are precise, and the difference between a "screening" and "diagnostic" colonoscopy determines whether you pay anything at all.
Screening colonoscopy (G0105 and G0121)
Medicare covers one screening colonoscopy every 10 years for average-risk patients 50 and older, or every 24 months for high-risk patients. Coverage is at 100% with no cost-sharing: no Part B deductible, no coinsurance, no copay. The 2026 Part B deductible of $283 is fully waived. Source: Medicare.gov colonoscopy coverage page.
Polyp removal during a screening (2026 special rule)
If the doctor finds and removes a polyp during what started as a screening colonoscopy, the claim shifts from preventive to therapeutic. Through 2026, you owe 15% coinsurance on the Medicare-approved amount, with no deductible. The coinsurance drops further to around 10% in 2027 and disappears entirely in 2030. This phaseout is part of the Consolidated Appropriations Act.
Diagnostic colonoscopy (CPT 45378)
A diagnostic colonoscopy ordered because of symptoms such as rectal bleeding, abdominal pain, or changes in bowel habits is billed under CPT 45378 and treated as standard Part B outpatient care. You owe:
- The annual Part B deductible: $283 in 2026
- 20% coinsurance on the Medicare-approved amount
If the Medicare-approved amount is $600, your share is $283 (deductible, if not yet met) plus $63.40 (20% of the remaining $317), totaling roughly $346 for that line item.
Cost by Insurance Type (2026 Summary)
| Insurance Type | Your Likely Out-of-Pocket (Screening) | Your Likely Out-of-Pocket (Diagnostic) |
|---|
| Medicare (Part B) | $0 | $283 deductible + 20% coinsurance |
| Medicare Advantage | $0 to small copay (plan-dependent) | Varies by plan |
| ACA marketplace plan | $0 (ACA requires preventive coverage) | Deductible + coinsurance |
| Employer insurance | $0 (ACA preventive mandate) | Deductible + coinsurance |
| Medicaid | $0 or minimal copay | Minimal or $0 |
| No insurance (self-pay) | $1,250 to $2,800 (ASC cash rate) | $1,250 to $8,500 (varies widely) |
Under the Affordable Care Act, all non-grandfathered health plans must cover screening colonoscopies as a preventive service with no cost-sharing. Per cancer.org, this applies to colonoscopies, FIT tests, Cologuard, and other USPSTF-recommended screening methods.
Common Colonoscopy Billing Errors
An estimated 49% to 80% of hospital bills contain errors, and colonoscopy is a high-error procedure due to its multiple billing components. The most common errors that cost patients money:
1. Screening billed as diagnostic. The most expensive mistake. If a preventive colonoscopy is coded as CPT 45378 (diagnostic) instead of G0121 or G0105 (screening), your cost shifts from $0 to potentially $1,000 or more. This can happen if the ordering physician documented symptoms the same day as the colonoscopy was scheduled, even if the procedure itself was a routine screening. Ask your gastroenterologist to confirm the code before the procedure.
2. Duplicate charges. Facility and physician bills arrive separately. Patients sometimes pay both, assuming they are from the same provider. Review each bill for what it covers before paying.
3. Anesthesia unbundled incorrectly. Anesthesia for a colonoscopy is a separate charge. Some facilities bill monitored anesthesia care (MAC) at inflated rates. The 2026 Medicare rate for anesthesia during colonoscopy is capped. Per MSN Healthcare analysis, incorrect anesthesia billing is a significant source of excess charges.
4. Pathology charges for biopsies. If tissue was sent to pathology, that generates a separate CPT charge. Verify pathology fees match the number of specimens actually collected.
5. Wrong facility fee category. Hospital outpatient departments are assigned Ambulatory Payment Classifications (APCs) that determine facility reimbursement. Incorrect APC assignment can inflate your bill.
The CoveredUSA Bill Analyzer cross-references each CPT code on your statement against the Medicare-set benchmark. Upload your colonoscopy bill at /medical-bill-analyzer to see which charges are within the expected range and which are statistical outliers.
How to Get an Accurate Colonoscopy Bill
Step 1: Request an itemized statement with CPT codes
You have a legal right to an itemized bill. Call the provider's billing department and ask specifically for an "itemized statement with procedure codes and diagnosis codes." Bills that only say "surgical services, $3,400" cannot be verified.
Step 2: Confirm the colonoscopy code
Look for CPT 45378 (diagnostic), G0105 (high-risk screening), or G0121 (average-risk screening). If a preventive colonoscopy shows up as 45378, call the billing office and ask them to verify the code against the physician's clinical notes.
Step 3: Compare each line to the Medicare rate
Medicare.gov's Procedure Price Lookup publishes the average amount billed and the Medicare payment for every CPT code by geographic area. If a charge on your bill is more than 4x the Medicare rate, that is a flag worth questioning.
Step 4: Apply for financial assistance
Most nonprofit hospitals are required to have charity care programs covering patients below 200% to 400% FPL. The 2026 FPL for a family of four is $33,000 (48 contiguous states). Additional programs:
- Blue Hope Financial Assistance (Colon Cancer Foundation): $300 stipend for uninsured patients below 200% FPL
- CDC Colorectal Cancer Control Program: Free or low-cost screening in participating states
- ColonoscopyAssist: Negotiated cash rates, typically $1,150 to $1,450
Step 5: Negotiate or appeal
Ask for the "prompt pay" or "self-pay" discount. For insured patients, file an appeal if a screening was billed as diagnostic. Appeals for miscoded colonoscopies succeed when physician documentation supports preventive intent. Per Medicare.gov, you have the right to appeal any coverage determination.
Ambulatory Surgery Centers vs. Hospitals: The Price Difference
Getting a colonoscopy at an ASC rather than a hospital outpatient department cuts total cost by 40% to 60%. Median total cost at a hospital outpatient department runs $1,475 to $3,500. At an ASC, the same procedure typically costs $700 to $1,800. For self-pay patients, asking your gastroenterologist to schedule at an ASC instead of a hospital can save $500 to $2,000 on a single visit.
Frequently Asked Questions
How much does a colonoscopy cost without insurance in 2026?
Without insurance, a colonoscopy at a hospital outpatient department typically runs $2,100 to $8,500 at chargemaster rates. Most hospitals offer a self-pay discount that reduces this to $1,500 to $3,500. An ambulatory surgery center cash price typically runs $1,250 to $2,800. Programs like ColonoscopyAssist and hospital charity care can bring costs down further for patients below 200% to 400% FPL.
What is the Medicare rate for CPT 45378 in 2026?
The 2026 Medicare-allowed amount for CPT 45378 is approximately $169 in a non-facility setting and $500 to $630 in a hospital outpatient department. These figures reflect the physician and facility components combined. The exact amount varies by geographic locality. The CMS Physician Fee Schedule Look-Up Tool at cms.gov provides the rate for your specific ZIP code.
Is a colonoscopy free under Medicare?
Screening colonoscopies are free under Medicare: no deductible, no coinsurance. Diagnostic colonoscopies (ordered for symptoms) are not free. You owe the $283 Part B deductible (2026) plus 20% coinsurance. If polyps are removed during a screening procedure, a 15% coinsurance applies through 2026, with no deductible.
What is the difference between CPT 45378 and G0121?
CPT 45378 is a diagnostic colonoscopy code used when the procedure is ordered because of symptoms. G0121 is a preventive screening colonoscopy code for average-risk Medicare patients. G0105 is used for high-risk patients. The billing code determines cost-sharing: G0105 and G0121 are covered at 100% with no cost. CPT 45378 triggers deductible and coinsurance. If you had a routine screening but received a bill with 45378, contact the billing office to verify the correct code.
Why is my colonoscopy bill so high compared to the Medicare rate?
Hospitals set chargemaster prices at 4x to 10x the Medicare rate as a negotiating baseline with insurers. Uninsured patients are often billed chargemaster rates automatically. Even insured patients may see bills that look large before the insurance adjustment is applied. Once the insurer applies its contracted discount, the amount drops significantly. If your Explanation of Benefits (EOB) shows charges significantly above contracted rates even after adjustment, you may have received a bill from an out-of-network provider. Always verify that your gastroenterologist, anesthesiologist, and the facility are all in-network before the procedure.
Can I dispute a colonoscopy bill that was coded incorrectly?
Yes. If a screening colonoscopy was billed as diagnostic, file a written appeal with your insurer or Medicare citing the physician's documentation of preventive intent. Attach any referral orders or clinical notes that show the procedure was scheduled as a routine screening. Most billing errors of this type are resolved when the physician submits a corrected claim with the appropriate G-code.
How do I find out if my colonoscopy bill has errors?
Request an itemized bill with CPT codes from the facility billing department and the physician billing department (they are often separate). Compare each CPT code to the Medicare rate using the Medicare Procedure Price Lookup or upload the bill to the CoveredUSA Bill Analyzer. Charges that are more than 4x to 5x the Medicare rate for the same code warrant a call to the billing department for an explanation.
What financial assistance programs exist for colonoscopies?
For uninsured and underinsured patients: hospital charity care (typically covers patients below 200% to 400% FPL), the Blue Hope Financial Assistance program ($300 stipend, requires income below 200% FPL), the CDC Colorectal Cancer Control Program (free screenings in participating states), and ColonoscopyAssist (negotiated cash rates). Payment plans through CareCredit and similar services are also available at many facilities.
The Bottom Line on Colonoscopy Costs in 2026
The 2026 Medicare rate for CPT 45378 is a matter of public record. What hospitals bill is often 4x to 10x that rate. The gap exists because most patients never look up the benchmark, never request an itemized bill, and never know they can negotiate.
If you are on Medicare, confirm your procedure is coded as a screening (G0105 or G0121) to avoid any cost-sharing. If you are uninsured, ask for an ASC instead of a hospital and request the self-pay rate before the procedure. If you received a bill that does not match what you expected, request the itemized statement with CPT codes and compare every line.
Upload your hospital bill to the free CoveredUSA Bill Analyzer to find errors, overcharges, and charity care options in 30 seconds.
