OA-135: Interim Bills Cannot Be Processed

What Does OA-135 Mean?

OA-135 is less common and appears when the interim bill rejection is classified as an administrative processing issue rather than a strict contractual obligation. The adjustment is informational — the payer is flagging that the interim bill cannot be processed but is not assigning financial responsibility to either the provider or the patient under a specific contractual term.

CARC 135 appears on your remittance when you submit an interim bill — a claim for ongoing inpatient or long-term care services before the patient is discharged — and the payer rejects it. This is a procedural rejection, not a clinical or coverage denial. The payer is not questioning whether the service was medically necessary or whether the patient has coverage. They are saying that the interim bill itself cannot be processed as submitted.

The most common trigger is using an incorrect type of bill (TOB) code. Interim billing requires specific frequency codes — xx2 for the first interim claim, xx3 for continuing interim claims, and xx4 for the last interim claim before the final bill. If the TOB code is wrong, the payer's system cannot identify the claim as an interim bill and will reject it. Other frequent causes include missing required fields (statement covers period, condition codes, occurrence codes), submitting a continuing interim bill when the payer has no initial interim claim on file, and submitting interim bills more frequently than the payer allows.

Some payers do not accept interim bills at all for certain service types. In those cases, the provider must hold all charges and submit a single final bill upon discharge. Before submitting interim claims, always verify the payer's specific interim billing requirements — including which facility types and service categories qualify, what frequency is allowed, and which data elements are required.

How to Resolve

Verify the payer's interim billing requirements, correct the bill type and required fields, and resubmit — or hold the claim for final billing at discharge.

1. Review the RARC for details The OA designation is broader, so the accompanying RARC code is especially important for understanding what specific interim billing requirement was not met.
2. Contact the payer for clarification If the OA adjustment is unclear, contact the payer to determine whether the issue is a system processing limitation or a policy requirement.
3. Correct and resubmit Address the identified issue and resubmit the interim bill, or convert to a final bill if interim billing is not supported.

How to Prevent OA-135

• Verify payer interim billing requirements before submission to avoid administrative processing rejections
• Keep current with payer policy changes that may affect interim billing acceptance

Also Filed As

The same CARC 135 may appear with different Group Codes:

Related Denial Codes