MA120 remark code

Remittance advice remark code MA120. Remark codes add detail to the reason code on the same claim line.

Missing or invalid CLIA number

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 MA120 means

The CLIA certificate number for the laboratory test is missing, incomplete or not valid.

Lab tests often need the CLIA number of the lab that performed them. This remark says the number was missing, wrong, or the certificate does not cover the test billed.

It usually comes with reason code 16 or a reason code about the provider's certification.

Common causes

• The CLIA number was not entered on a claim with lab tests.
• The number was entered in the wrong field or with a typo.
• The lab's certificate level does not cover the complexity of the test billed.

What to do next

1. Confirm the lab's CLIA number and certificate type.
2. Check that the certificate covers the tests billed.
3. Send a corrected claim with the right CLIA number.

Related codes

• 16 (reason code) Missing information or billing error
• MA114 (remark code) Missing or invalid service location