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

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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pricing references are from the CMS Medicare Physician Fee Schedule and public charge benchmarks and may be outdated.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.