OA-100: Payment Made to Patient/Insured

What Does OA-100 Mean?

OA-100 is the most common pairing for this code. The OA group designation indicates the payment direction is an administrative issue that does not fall into contractual obligation or patient responsibility in the traditional sense. The claim was paid correctly in terms of amount — the issue is solely where the payment was sent. The provider's next step depends on whether an AOB was in place and whether the payer will reprocess.

CARC 100 appears on your remittance when the payer processed and paid the claim, but directed the payment to the patient, the insured individual, or the responsible party rather than to the provider. This is fundamentally different from a denial — the payer is not disputing the service, the coding, or the medical necessity. They are simply informing you that the check or EFT went to the patient's address instead of yours.

The most common trigger is a missing Assignment of Benefits (AOB) form. Without a signed AOB on file, the payer has no authorization to send payment to the provider and defaults to paying the patient. Out-of-network status is the second most frequent cause — many payers automatically direct payment to the patient when the rendering provider is not in their network, regardless of whether an AOB exists. Other causes include incorrect billing information (wrong NPI, tax ID, or pay-to address), coordination of benefits errors where the wrong entity receives payment, and terminated coverage situations.

From a workflow standpoint, CARC 100 creates a patient collection scenario rather than a payer dispute. The money is out the door and in the patient's hands. Your options are to collect from the patient, or to contact the payer and request reprocessing if you believe the payment was misdirected due to a payer error (such as an AOB being on file but ignored). Either way, prompt follow-up is essential because the longer the delay, the harder it becomes to recover funds from the patient.

Common Causes

How to Resolve

Determine why payment went to the patient, then either collect from the patient or request payer reprocessing if an AOB was on file.

1. Verify AOB and payment routing Check whether a signed AOB is on file with the payer. If the AOB was submitted but the payment was still sent to the patient, this is a payer processing error.
2. Request reprocessing or collect from patient If the AOB was on file, submit a reprocessing request with a copy of the AOB. If no AOB exists, contact the patient to collect the payment that was sent to them.
3. Update patient account records Move the balance from insurance receivables to patient responsibility. Track the outstanding amount and follow your patient collections workflow.
4. Prevent future occurrences Submit a new AOB to the payer and confirm it is properly recorded for all future claims from this patient.

Common RARC Pairings

The RARC code tells you exactly what triggered the OA-100:

How to Prevent OA-100

• Obtain a signed Assignment of Benefits form from every patient during registration and confirm it is on file with each payer
• Verify the provider's billing information (NPI, TIN, pay-to address) is correct on every claim before submission
• For out-of-network patients, inform them upfront that payment may be sent to them directly and establish a collection process
• Audit remittances regularly to catch patient-directed payments early and follow up promptly

General Prevention

• Obtain a signed Assignment of Benefits (AOB) form from every patient during registration and ensure it is submitted to the payer with the claim
• Verify that the provider's billing information (NPI, tax ID, billing address, pay-to address) is accurate on every claim before submission
• For out-of-network patients, inform them that payment may be sent to them directly and establish a process for collecting those payments
• Implement a process to check AOB status with the payer before submitting claims, especially for new patients or new insurance plans
• Audit remittances regularly to catch instances of patient-directed payments early and follow up promptly
• Maintain current credentialing and enrollment status with payers to ensure payment is directed to the provider

Also Filed As

The same CARC 100 may appear with different Group Codes:

Related Denial Codes