Denial Code Decoder

MA27 — Member entitlement number problem

The patient's entitlement or member identifier on the claim is missing or invalid — for Medicare, usually a wrong or outdated Medicare Beneficiary Identifier (MBI). The coverage may be fine; the number on the claim is not.

Billable to the patient? No — correct the identifier and resubmit first.

Where it strikes

Where this denial is born

Front desk
Coding
Claim build
Submission
Adjudication

This denial is usually created at the highlighted stage — that is where prevention lives.

Work the denial

Answer the questions — follow the path

The same questions an experienced biller asks, in order. Your answers draw the route to the right action.

Does an eligibility check return the current, valid member ID?

Every path

The full decision tree

Does an eligibility check return the current, valid member ID?

Yes →
Correct the member ID and resubmit. Update registration with the identifier from the eligibility response and resubmit the claim.
No →
Confirm coverage with the patient. The coverage itself may have changed — verify with the patient and their payer, then update registration and resubmit to the right plan.

Stop the repeat

Prevention

Run an eligibility check at every visit and let it correct the member ID on file — identifiers change (MBIs can be reissued) and cards go stale.

Go deeper

The code list, and when it was last checked

X12 maintains the Remittance Advice Remark Codes list, where this code is listed as MA27. A remark code carries no adjustment group of its own — the group you see on the remittance line belongs to the reason code it arrived with. It has been on the list since January 1, 1997, and X12 last revised its entry on February 28, 2003.

Checked against the list revision dated July 1, 2026 on August 7, 2026, where it reads as an active code.

X12 — Remittance Advice Remark Codes (opens in a new tab)

Check the reasoning