M50 remark code

Remittance advice remark code M50. Remark codes add detail to the reason code on the same claim line.

Missing or invalid revenue code

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What M50 means

A revenue code on the claim is missing, incomplete or not valid for the service or type of bill.

Revenue codes tell the payer which department or cost center a facility charge belongs to. The payer is saying a line had no revenue code, an invalid one, or one that does not fit the type of bill or service.

It normally comes with reason code 16 and the line or claim is returned for correction rather than denied on its merits.

Common causes

• The charge master assigned an outdated or incorrect revenue code to the item.
• A revenue code was paired with a HCPCS code or type of bill that it cannot be used with.
• The revenue code field was left blank on one or more lines.

What to do next

1. Check the revenue code against the service, the HCPCS code and the type of bill.
2. Fix the charge master entry if the same error is likely to repeat.
3. Send a corrected claim with the right revenue code.

Related codes

• 16 (reason code) Missing information or billing error
• M20 (remark code) Missing or invalid HCPCS code
• M49 (remark code) Missing or invalid value code or amount