CARC 165: Referral Absent

What it means

The payer denied this claim because it did not receive a required referral from the patient's primary care provider or referring provider authorizing the service. Many plans, especially HMOs and managed care products, require a referral on file before a specialist or facility can be reimbursed.

Common causes

No referral was obtained before the service was rendered
Referral was obtained but not submitted with the claim
Referral was submitted but did not match the billed provider, date of service, or service type
Referral had expired or exceeded its authorized visit count before the service date
Referral was on file but not properly linked to the claim in the payer's system

How to fix it

Confirm whether the patient's plan actually requires a referral for the billed service
Contact the referring provider's office to verify a referral was generated and obtain the referral number or documentation
Check that the referral covers the correct servicing provider, specialty, date range, and number of visits
Resubmit or correct the claim with the referral number in the appropriate claim field (e.g., box 17a/referral loop)
If a valid referral existed at time of service, submit it as supporting documentation with a corrected claim or appeal
If no referral existed, obtain a retroactive/backdated referral if the payer allows one, or discuss financial responsibility with the patient

Appeal / resubmit

Gather proof that a valid referral existed at the time service was rendered, such as the referral authorization number, date range, and referring provider details. Submit a corrected claim if the referral was simply omitted, or file an appeal with the referral documentation attached if it was on file but not properly matched. Include a clear explanation showing the referral covers the exact provider, date of service, and service type. Always check payer-specific timely filing and appeal deadlines before submitting.

Related codes

Frequently asked

Does every plan require a referral?

No. Referral requirements depend on the specific insurance plan type, such as HMO or managed care products. PPO plans typically do not require referrals, so it's important to verify the patient's plan rules before assuming this denial applies.

Can I bill the patient if no referral was obtained?

This depends on payer policy and any patient agreements you have in place, such as an Advance Beneficiary Notice or similar waiver signed before the service. Review your payer contract and applicable state regulations before billing the patient.

What if the referral existed but wasn't attached to the claim?

In that case, submitting a corrected claim with the referral number included, or providing the referral documentation in an appeal, may resolve the denial.

More free billing tools: all denial codes · denial lookup · Medicare fee calculator

This content is informational only and does not constitute billing or legal advice. Always verify requirements with the specific payer and consult qualified compliance or legal counsel as needed.