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Denial code CO-55: what it means and what to do
Denial code CO-55 on your Explanation of Benefits: The plan considers the treatment experimental or investigational.
Check my letter freeWhat CO-55 means
The plan considers the treatment experimental or investigational.
CO means contractual obligation: under its contract, the provider is usually responsible for this amount, so an in-network provider generally should not bill you for it.
What to do
Ask your doctor for a letter with the medical studies that support the treatment.
If the plan says no again, you can ask for an external review by independent doctors.
Your deadline
Most plans give you 180 days from the denial notice to file an internal appeal. Original Medicare gives 120 days from the Medicare Summary Notice, and Medicare Advantage plans 65 days from their decision. Check the date printed on your letter.
More on this reason: Experimental or investigational.
Other denial codes
- CO-50
- CO-197
- CO-198
- CO-15
- CO-16
- CO-18
- CO-97
- CO-4
- CO-11
- CO-29
- CO-96
- CO-204
- CO-119
- CO-167
- CO-242
- CO-22
- CO-109
- CO-27
- CO-26
- CO-31
- CO-45
- PR-1
- PR-2
- PR-3