CARC 66 Active

OA-66: Blood Deductible

TL;DR

Adjustment in a COB or secondary payer context. Review the coordination of benefits details to determine the responsible party.

Action
Verify & Resubmit
Who Pays
Depends
Appeal
Yes
Patient Impact
Indirect
Disclaimer
This content is for informational purposes only and does not constitute professional billing advice. Always verify information against your payer contracts and current coding guidelines. Consult a certified billing specialist for specific claim issues.

What Does OA-66 Mean?

With OA (Other Adjustments), CARC 66 typically appears in a coordination of benefits (COB) context. Secondary payer applies blood deductible. The financial responsibility depends on the specific arrangement between payers — review the primary payer's EOB and the COB terms to determine the correct course of action.

CARC 66 appears on a remittance when the payer adjusts payment for the blood deductible. This is a standard plan-defined cost-sharing amount that the patient is obligated to pay per their insurance benefits. The code confirms the payer processed the claim correctly and applied the plan's benefit structure as designed.

Common scenarios that trigger this adjustment include: medicare requires the patient to pay for the first 3 pints of blood per calendar year (blood deductible); Patient or blood bank did not replace the blood units, triggering the deductible; Patient has not met the annual 3-pint blood deductible. The group code paired with CARC 66 determines who bears the financial responsibility — PR shifts it to the patient, CO places it on the provider as a contractual obligation, OA indicates a coordination of benefits or other payer adjustment.

Common Causes

Cause Frequency
Secondary payer blood deductible Secondary payer applies blood deductible Most Common

How to Resolve

  1. Review the coordination of benefits Examine the OA-66 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. Appeal or resubmit if needed Appeal if the blood deductible was already met or blood was replaced.
  5. Follow up Monitor the claim status and take additional action as needed based on the COB determination.
Appeal Guide

Appeal if the blood deductible was already met or blood was replaced.

Common RARC Pairings

The RARC code tells you exactly what triggered the OA-66:

RARC Description
N381 Consult contract/fee schedule Review blood deductible terms →

How to Prevent OA-66

Also Filed As

The same CARC 66 may appear with different Group Codes:

PR-66 CO-66

Related Denial Codes

OA-1 — Deductible Amount OA-2 — Coinsurance Amount OA-3 — Co-payment Amount OA-24 — Charges Covered Under Capitation/Managed Care OA-40 — Charges Do Not Meet Emergent/Urgent Care Qualifications

Sources

  1. https://x12.org/codes/claim-adjustment-reason-codes
  2. https://revenuecyclemgmt.com/claim-adjustment-reason-codes/
  3. https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c22pdf.pdf
  4. Codes maintained by X12. Visit x12.org for official definitions.