Not legal advice - Denial Decoder helps you understand insurance denials; it doesn't replace a licensed attorney, doctor, or patient advocate.

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CO group

CO-50 Denial Code

What it means

The insurer decided this care wasn't medically necessary, so it won't pay. This second-guesses your doctor's judgment.

Why it happens

The plan's clinical reviewer felt the documentation didn't meet its medical-necessity criteria (e.g., conservative treatment not tried first).

What to do

This is one of the most winnable appeals (~70% overturned). Get a letter of medical necessity from your doctor, address the exact criterion cited, and file an internal appeal; escalate to external review if needed.

Can you appeal it?

Yes - strong appeal candidate.

Official description

Non-covered service because it is not deemed a 'medical necessity' by the payer.

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