Medicare Denied Claim as Experimental Treatment

What This Means

Medicare reviewed your claim and determined that the service or treatment is considered experimental or investigational. On your MSN or EOB this typically appears as CARC CO-55 (procedure/treatment/drug deemed experimental/investigational by the payer) or CO-50 (not deemed medical necessity). In Medicare’s view, the treatment has not yet been proven safe and effective through enough research to be considered a standard, accepted medical practice.

This does not necessarily mean the treatment is unsafe or will not help you. It means Medicare’s coverage rules do not yet include it.

Why This Happens

• The treatment is not FDA-approved for your condition. A drug or device may be approved for other uses but not for the condition listed on your claim.
• Medicare has no National or Local Coverage Determination for the service. Medicare relies on coverage policies (NCDs and LCDs) to decide what is covered. If a service is not addressed in these policies, or is explicitly excluded, it may be denied as experimental.
• The treatment is part of an ongoing clinical study. Services that are still being evaluated in clinical trials are generally not covered, though routine care costs during a qualifying trial may be covered under National Coverage Determination 310.1.
• There is not enough published evidence. Even if some doctors support the treatment, Medicare may consider it experimental if it lacks large-scale peer-reviewed studies.

Should You Appeal?

What To Do Next

1. Read your denial notice carefully. Look for the specific reason the service was called experimental. This will help you understand whether the denial might be based on a coding error or a genuine coverage exclusion.
2. Talk to your doctor. Ask whether published peer-reviewed studies or clinical practice guidelines support this treatment as a standard of care. If so, your doctor’s help will be critical for any appeal.
3. Check if you qualify for a clinical trial exception. Medicare covers routine care costs in qualifying clinical trials. If your treatment is part of such a trial, the routine costs (like lab tests, imaging, and doctor visits) should be covered even if the experimental treatment itself is not.
4. Consider filing an appeal if there is a reasonable basis. If your doctor believes the service is standard care that was mislabeled, or if routine clinical trial costs were wrongly denied, submit an appeal with supporting medical literature.
5. Look into other coverage options. Some treatments may be covered under a manufacturer’s compassionate use program or a clinical trial at no cost to you. Ask your doctor about these options.

Sources

• Social Security Act § 1862(a)(1)(A) (42 USC § 1395y) — the statutory “reasonable and necessary” standard Medicare uses to exclude experimental services.
• CMS: Medicare Coverage of Clinical Trials — National Coverage Determination 310.1 on routine patient-care costs during qualifying clinical trials.
• CMS: Coverage With Evidence Development — pathway by which Medicare may cover otherwise-investigational items inside an approved study.
• 42 CFR 411.15: Particular services excluded from coverage — the regulatory list of excluded services, including not-reasonable-and-necessary items.
• X12: Claim Adjustment Reason Codes (CARCs) — official definitions of CO-55 and CO-50.
• Medicare.gov: Original Medicare appeals — formal appeal process and 120-day filing deadline.

Frequently Asked Questions