On your explanation of benefits or remittance, CO-50 means: non-covered because not deemed medically necessary.
How often this type of denial gets overturned
Where state external-review programs publish outcomes for this denial category, the overturn rates are (reported separately — different programs, different denominators):
Program
Overturn rate
Cases
California DMHC IMR
55.1%
31,504
New York DFS
48.2%
54,234
Roughly half of externally reviewed denials in this category are overturned. A denial is a first decision, not a final one.
What to do next
This code is generally appealable. Internal appeal deadlines are typically 180 days from the denial.
If your denial arrived near-instantly or names no reviewing physician, several states now bar algorithm-only medical-necessity denials — ask in writing who reviewed the claim.
Always request an itemized bill and keep everything in writing.
Fighting a denial or a surprise bill? Medigami turns these public records into your specific next step — appeal winnability, benchmarked bills, and generated letters. medigami.com