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MA39 Remark Code: Missing or Invalid Patient Gender

MA39 means the gender reported for the patient is missing, incomplete, or invalid. The payer could not accept the value, or it conflicts with the member's record, so the claim needs a corrected gender entry.

Code: MA39 (RARC MA39)
Status: Active In use since January 1, 1997; last modified February 28, 2003.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The provider must correct the claim. A data error is not billable to the patient.
Official description: Missing/incomplete/invalid gender.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What MA39 means

MA39 reports that the patient’s gender field could not be accepted. The value might be blank, use a code the payer does not accept, or disagree with the member record. Because payers run gender-related edits on procedures and diagnoses, a problem with this field can also trigger CARC 7 or 10 on specific lines.

Unlike MA21, which is a combined name-and-sex check against Social Security data, MA39 concerns the gender field itself.

Common causes

Registration left the field blank or used an unknown value.
The value differs from the payer’s enrollment record.
The claim includes a gender-specific service and no indicator explaining why it applies.
The practice management system sends a value the payer’s format does not support.

How to fix it

Check the eligibility response for the gender on file with the payer.
Correct box 3 or form locator 11.
Add any payer-required indicator if a gender-specific service is appropriate for this patient.
Resubmit the claim, using resubmission code 7 in box 22 if you are replacing a processed claim.

How to prevent it

Make gender a required registration field, compare it with eligibility data, and set up alerts for gender-specific services that may need an indicator. A Claims Validator can flag these conflicts before submission.

Codes that may appear with MA39

CO-16 (Claim/service lacks information or has submission/billing error(s).): Required information is missing or invalid, with MA39 identifying the gender field.
CO-7 (The procedure/revenue code is inconsistent with the patient's gender.): The procedure or revenue code is inconsistent with the patient's gender.
CO-10 (The diagnosis is inconsistent with the patient's gender.): The diagnosis is inconsistent with the patient's gender.

MA21 (SSA records indicate mismatch with name and sex.): Name and sex do not match Social Security records.
MA36 (Missing/incomplete/invalid patient name.): The patient name is missing or invalid.
MA27 (Missing/incomplete/invalid entitlement number or name shown on the claim.): The entitlement number or name is missing or invalid.

MA39 FAQ

Where is the patient's sex reported?

Box 3 on the CMS-1500 and form locator 11 on the UB-04. Electronic claims carry it in the patient demographic segment.

What if a service is gender-specific but clinically appropriate?

Some payers use a condition code or modifier to show that a gender-specific service is appropriate for the patient. Medicare, for example, has used condition code 45 and modifier KX for this purpose. Check the payer's current instructions.

Should the claim match the payer's record?

Generally yes. Use the value in the payer's eligibility response to avoid a mismatch.

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