OA-133: Service Line Pending Further Review

What Does OA-133 Mean?

When paired with Group Code OA, CARC 133 (Service Line Pending Further Review) is processed as an adjustment outside the standard CO/PR classifications. This typically occurs in secondary payer or coordination of benefits scenarios. Review the remittance details and the COB arrangement to determine financial responsibility and appropriate next steps.

CARC 133 appears on a remittance when the payer applies an adjustment for service line pending further review. Review the group code and any accompanying RARC codes to understand the full context of this adjustment.

Common scenarios that trigger this adjustment include: the payer has requested additional documentation (medical records, clinical notes, etc.) to complete the adjudication of the claim and is holding the service line pending receipt; The claim has been selected for medical review, prepayment audit, or clinical review, and the payer is holding the payment until the review is completed; The payer is investigating other potential insurance coverage for the patient and is holding the claim pending COB determination. The group code paired with CARC 133 determines who bears the financial responsibility — OA indicates a coordination of benefits or other payer adjustment, CO places it on the provider as a contractual obligation, PR shifts it to the patient.

Common Causes

How to Resolve

1. Review the coordination of benefits Examine the OA-133 adjustment to understand how it fits within the primary/secondary payer relationship or other multi-payer context.
2. Verify primary payer adjudication Review the primary payer's EOB to understand the basis for the secondary payer's OA adjustment.
3. Determine the responsible party Based on the COB review, identify whether the adjustment should be absorbed, billed to another payer, or if additional documentation is needed.
4. Follow up Monitor the claim status and take additional action as needed based on the COB determination.

Common RARC Pairings

The RARC code tells you exactly what triggered the OA-133:

How to Prevent OA-133

• Submit complete clinical documentation with the initial claim to reduce documentation request delays
• Verify prior authorization status before claim submission
• Maintain accurate patient insurance information to prevent COB investigation delays
• Respond to payer documentation requests within the specified timeframe
• Track claim aging and follow up proactively on claims approaching payer processing deadlines

Also Filed As

The same CARC 133 may appear with different Group Codes:

Related Denial Codes