N533 Remark Code: IHS Facility and Tribal Health Plan
N533 means the payer's decision is based on the service being performed in an Indian Health Service (IHS) facility for a patient covered by a self-insured tribal group health plan. That combination is subject to special payer-order and payment rules, which the payer is applying.
Quick facts
- Code
- N533 (RARC N533)
- Status
- Active In use since July 1, 2010.
- Code set
- Remittance Advice Remark Codes (RARC)
- Group codes
-
- OA (Other Adjustment): The remark explains a coordination or payment determination tied to the IHS and tribal plan setting.
- CO (Contractual Obligation): If it adjusts a provider claim, the amount is not shifted to the patient. Tribal members generally are not billed for IHS services.
- Official description
Services performed in an Indian Health Services facility under a self-insured tribal Group Health Plan.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026- Last verified
- against the official X12 list.
What N533 means
N533 describes a specific setting rather than a billing error: the service was performed in an Indian Health Service facility, and the patient’s coverage is a group health plan that a tribe self-insures. Payer order and payment rules for that combination differ from the usual employer plan and Medicare interactions, and the payer is citing it as the basis for how it handled the claim.
The remark was added in 2010, a few months after a set of Medicare Secondary Payer recovery remarks, and its subject is similar: which coverage pays first when Medicare and a tribal plan are both involved. A later companion, N801, covers similar tribal plan situations in Medicare participating and critical access hospital facilities.
What to do
- Confirm the facts the payer relied on: that the facility is an IHS facility and that the patient’s plan is a self-insured tribal group health plan.
- Ask the payer which rule it applied and what it expects next, for example billing another payer or taking no action.
- Coordinate with the tribal plan administrator if payer order is disputed.
- Correct the claim or COB information if the facility type or plan information on the claim was wrong, and resubmit.
- Do not bill IHS-eligible patients while the payers resolve responsibility.
Keeping records straight
Facilities that serve tribal members should record each patient’s tribal plan status and the plan’s self-insured status at registration. Clear coverage records make it easier to respond when a payer applies N533 or a related tribal coverage remark.
Codes that may appear with N533
Related and easily confused codes
- N801 (Services performed in a Medicare participating or CAH facility under a self-insured tribal Group Health Plan, in accordance with Federal Regulation…): A related remark for services in a Medicare participating or critical access hospital facility under a self-insured tribal group health plan.
- N757 (Adjusted based on the Federal Indian Fees schedule (MLR).): Payment adjusted based on the federal Indian fee schedule.
- N530 (Not Qualified for Recovery based on enrollment information.): Not qualified for recovery based on enrollment information.
N533 FAQ
Who typically sees N533?
IHS facilities, tribal health programs, and payers coordinating with them, including Medicare in recovery situations. Most private practices will not encounter it.
Why does a self-insured tribal plan get special treatment?
Federal law and CMS policy include specific provisions for tribal plans and services furnished through IHS. The details depend on the facility, the plan, and the payer involved, so confirm with the payer which rule it applied.
Can the patient be billed?
IHS-eligible patients generally are not charged for services at IHS facilities. Resolve the claim between the payers.