MA01 Remark Code: What It Means & How to Fix It (2026)

What Does MA01 Remark Code Mean?

MA01 is a Medicare Remittance Advice Remark Code (RARC) that means: "If you do not agree with what we approved for these services, you may appeal our decision."

However, MA01 is most commonly seen paired with other denial codes (like CO 16 or CO 22) in the context of coordination of benefits (COB) issues where Medicare or another payer could not identify secondary insurance information.

When You'll See MA01

MA01 typically appears on Medicare remittance advice (RA) when:

• Medicare is the primary payer and processed the claim, but is alerting you to appeal rights


• The claim was processed but payment was reduced or denied


• Coordination of benefits information may be incomplete

How to Resolve MA01 Issues

If MA01 Appears with a Denial (CO 16, CO 22, etc.)

• Check the primary denial code — MA01 is informational; the CARC code tells you why the claim was denied


• Verify coordination of benefits — Ensure Medicare has the correct primary/secondary payer information


• Contact Medicare — Call the Medicare Administrative Contractor (MAC) to update COB information


• Resubmit the claim — Once COB information is corrected, resubmit

If MA01 Appears with Payment

MA01 on a paid claim is simply informing you of your appeal rights. No action needed unless you disagree with the payment amount.

Updating Coordination of Benefits

If the issue is COB-related:

• Contact the Benefits Coordination & Recovery Center (BCRC): 1-855-798-2627


• Submit a COB update form to Medicare


• Verify with the secondary payer that they have the correct Medicare information


• Resubmit the claim after COB records are updated

MA01 vs Related Remark Codes

| Code | Meaning |
|------|---------|
| MA01 | Alert about appeal rights / COB issues |
| MA04 | Secondary payer not liable |
| MA07 | Missing/incomplete authorization number |
| MA130 | Missing clinical records |
| N19 | Missing plan information |

Common Scenarios

Scenario 1: Medicare Advantage Crossover

Medicare processed the claim but the supplemental (Medigap) payment didn't cross over. Check that the Medigap insurer code is on file with Medicare.

Scenario 2: Workers' Comp / Auto Accident

Medicare denied as secondary but another payer should be primary. Update the Medicare Secondary Payer (MSP) record with the correct primary payer.

Scenario 3: New Medicare Beneficiary

Patient recently enrolled in Medicare and their COB records haven't been updated yet. Contact BCRC to ensure proper payer sequencing.

Prevention Tips

• Verify insurance order at every visit — Confirm primary and secondary payer information


• Submit MSP questionnaire — Ensure Medicare has current information about other coverage


• Check eligibility before service — Use your clearinghouse to verify Medicare as primary or secondary


• Keep COB information updated — When patients change insurance, update Medicare promptly

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Related Denial Code Guides

• Complete CARC & RARC Denial Code Reference Guide


• CO 50 Denial Code Guide — Medical necessity


• CO 11 Denial Code Guide — Diagnosis mismatch


• CO 16 Denial Code Guide — Missing information


• CO 97 Denial Code Guide — Bundling/NCCI edits


• MA01 Remark Code Guide — Medicare COB


• N479 Remark Code Guide — Missing documentation