RARC M38: Missing or Invalid Referring Provider Information
The referring or ordering provider information on the claim is missing or invalid — verify the provider's NPI and credentials, then resubmit with complete referral data.
What Does RARC M38 Mean?
M38 indicates that the payer cannot process the claim because the referring or ordering provider's information is absent, incomplete, or fails validation. Many services — particularly diagnostic tests, specialist consultations, DME orders, and home health services — require a referring or ordering provider to be identified on the claim. The payer uses this information to verify that the service was properly ordered by an authorized provider and, in some cases, to confirm that a valid referral is on file.
The most frequent trigger for M38 is a missing or incorrect NPI for the referring provider. Medicare requires the ordering or referring provider's NPI on claims for diagnostic tests, DME, and other ordered services, and will reject claims where this field is blank or contains an NPI that does not match an active, enrolled provider. Commercial payers with referral requirements may also deny claims when the referring provider's information is missing or does not match their network records.
M38 typically accompanies CARC 16 (missing information) or CARC 4 (inconsistency between claim data). When the referring provider's NPI is valid but the provider is not enrolled with the payer (for example, a Medicare ordering provider who has opted out), a different remark code may be used, but M38 can sometimes surface in these situations as well.
What to Do
Locate the referring or ordering provider's NPI and verify it is correct and active using the NPPES NPI Registry. Confirm that the provider is enrolled with the payer as a referring or ordering provider — for Medicare, this means the provider must have an approved Medicare enrollment. Populate the referring provider fields on the claim with the correct NPI, name, and any other required identifiers. Resubmit.
For practices that rely heavily on referrals and orders — such as laboratories, imaging centers, and DME suppliers — building a validated provider directory that your billing team references when entering referring provider data can significantly reduce M38 denials. Flag any orders that arrive without a clear referring provider NPI before the claim is generated, rather than submitting and waiting for the denial.
Common Scenarios
- A laboratory submits a claim for blood work without the ordering physician's NPI because the requisition form only contained the physician's name, and the billing team did not look up the NPI before claim submission.
- A specialist's claim is denied because the referring provider's NPI entered on the claim belongs to a retired physician whose NPI is no longer active in the payer's system.
- A home health agency bills Medicare for services but enters the agency's organizational NPI in the referring provider field instead of the individual physician's NPI who ordered the services.
Commonly Paired With
No common pairings documented yet.