When a Medicare Advantage plan says a service is "not medically necessary," it has to base that on Medicare's coverage rules. CMS says plans must follow Original Medicare's coverage rules, including national and local coverage determinations. A plan can use its own criteria only when Medicare's rules aren't fully set. Ask the plan which rule it used, and answer that rule in your appeal, which you generally must file within 65 days.
What does "not medically necessary" mean?
It means the plan decided the service didn't meet its standards for being needed for your condition. It doesn't always mean your doctor was wrong. Sometimes a key note is missing from the records, or the request used the wrong code.
That's why the first step is finding out exactly what standard the plan applied.
What rules must the plan follow?
CMS's 2024 rule (CMS-4201-F) says Medicare Advantage plans must comply with:
- National coverage determinations (NCDs): Medicare-wide rules for certain services.
- Local coverage determinations (LCDs): rules set by regional Medicare contractors.
- General coverage and benefit conditions in Original Medicare regulations.
The federal rule, 42 CFR 422.101, says this covers rules for things like hospital admissions, nursing home care, home health and inpatient rehab.
When can a plan use its own criteria? CMS says only when Medicare's coverage criteria aren't fully established. Then the plan can write its own criteria. They have to be based on current evidence from widely used treatment guidelines or medical research. And they must be public.
You can look up many Medicare coverage rules at Medicare.gov/coverage. Your doctor's office may also know the relevant NCD or LCD.
Who reviewed the denial?
Under 42 CFR 422.566, a doctor or other qualified health professional has to review a medical necessity denial before the plan sends it. That reviewer needs expertise in the right field and must know Medicare's coverage rules.
It's fair to ask the plan about this.
How do I ask which criteria the plan used?
Call member services, or write to the plan. Be specific.
What to say:
"I received a denial dated [date] for [service] saying it wasn't medically necessary. Can you tell me the specific coverage rule or criteria you used? Was it a Medicare national or local coverage determination, or the plan's own criteria? If it was the plan's own criteria, where are they published? Who reviewed the decision, and what was their specialty?"
Ask them to send the answer in writing, or note the date, time, and name of the person you spoke with.
Sample written request:
"Please send me the specific coverage criteria used to deny [service] on [date], member [name]. If you used your own criteria, please tell me where they're posted. Please also tell me why Medicare's rules weren't fully set for this service."
How do I use the criteria in an appeal?
Once you know the rule, your appeal can answer it point by point.
- List each requirement in the rule. For example, "tried other treatment for 6 weeks" or "needs daily skilled care."
- Match each one to something in your medical records.
- Ask your doctor for a letter that addresses the requirements directly.
- Point out if the plan used its own criteria where a Medicare rule exists, or if its criteria aren't public.
What to ask your doctor's office:
"My Medicare Advantage plan denied [service] as not medically necessary under [rule or criteria]. Could the doctor write a letter explaining how I meet each part of that rule? The appeal deadline is [date]."