HCPCS code

G0121Screening colonoscopy, average-risk patient

Plain-English reference for HCPCS G0121. What it covers, what it typically costs, and the billing errors patientbill.org looks for on this code.

Typical setting
Hospital outpatient or ASC
Medicare allowable
$390
Common private-payer range
$1,000 – $5,000

The Medicare allowable is the national non-facility rate from the CMS Physician Fee Schedule and is the most defensible "fair price" anchor. Commercial charges typically run 2–5× this number; hospital list prices can be much higher still.

What this code actually is

HCPCS G0121 is a screening colonoscopy for an average-risk patient. Covered at $0 under ACA-compliant plans and Medicare. If polyps are removed, the procedure is sometimes recoded — but federal rules still require it to be covered as preventive without coinsurance.

Audit issues we look for on G0121

  • Preventive miscoding — service is ACA-preventive but billed with patient cost-sharing

Think your bill has the wrong G0121 charge?

Upload the bill and we'll check for upcoding, unbundling, duplicates, and prices above what's reasonable. If we recover money for you, we keep a small contingency fee. If we don't, you owe nothing.

Common questions about CPT G0121

Private-payer charges typically fall in the $1,000 – $5,000 range, though hospital list prices can run much higher. Medicare's allowable rate for G0121 is roughly $390, which is a useful fair-price anchor. If your bill for this code is significantly above the high end of that range, ask for an itemized statement and compare against your Explanation of Benefits (EOB) — the insurance "allowed amount" is the most defensible reference point.

Related codes in Minor procedures & surgery

Patientbill.org is not affiliated with any provider, insurer, or the AMA. Code descriptions are CMS-published short descriptors plus our own plain-English explanations; pricing references are from the CMS Medicare Physician Fee Schedule and public charge benchmarks and may be outdated. Verify your specific charges against your EOB.