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CO-53 Denial Code: Services by Immediate Relative

CO-53 means the payer won't cover the service because it was furnished by an immediate relative of the patient or a member of the patient's household. Many plans, including Medicare, exclude such services. It generally can't be fixed by correcting the claim unless the relationship was reported in error.

Quick facts

Code
CO-53 (CARC 53)
Status
Active In use since January 1, 1995.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The usual group. The provider can't bill the patient on this denial; the service is excluded.
  • PR (Patient Responsibility): Occasionally used when the plan assigns the excluded amount to the patient. Given the family relationship, practices typically write it off; follow your policy and compliance guidance.
Official description
Services by an immediate relative or a member of the same household are not covered.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-53 means

CARC 53 says services by an immediate relative or a member of the same household are not covered. Many health plans exclude care furnished by a family member or a person living with the patient. The rules are meant to prevent billing for care that might otherwise be given for free or that’s hard to verify independently.

Medicare has a well-known version of this exclusion. It lists specific relationships, including spouses, parents, children, siblings, step-relatives, in-laws, grandparents, and grandchildren, and it applies to services furnished by the physician or supplier or by people working under them in certain arrangements. Commercial plans often have similar provisions in their plan documents.

Common causes

  • A clinician treating a family member and billing the patient’s insurance.
  • Household members providing services such as home care, therapy, or transportation that are billed to the plan.
  • Group practice arrangements where the relative is the billing or supervising provider.
  • Payer data errors matching the patient and provider as relatives or household members, for example from shared addresses.

How to fix it

  1. Confirm the relationship between the patient and the rendering, supervising, or billing provider.
  2. If the relationship is real, accept the exclusion. Adjust the balance according to your policy and compliance guidance.
  3. If the payer’s information is wrong, contact the payer with evidence, such as different addresses or no family relationship, and ask for reprocessing or appeal.
  4. If another, unrelated provider actually rendered the service, send a corrected claim with the correct rendering provider (box 24J) and resubmission code 7 in box 22.

How to prevent it

  • Screen for family relationships when scheduling, especially in small practices and home-based services.
  • Refer family members to an unrelated clinician when possible.
  • Know each payer’s exclusion rules, including which relationships and practice arrangements they cover.
  • Train staff that treating relatives can create billing and ethical issues beyond this denial.

Specialty notes

Home health, personal care, and behavioral health services delivered in the home are more likely to involve household members as caregivers. Some Medicaid programs have specific rules allowing paid family caregivers, so check program rules rather than assuming the exclusion applies.

Remark codes that may appear with CO-53

  • N425 (Statutorily excluded service(s).): The service is statutorily excluded, as Medicare's relative exclusion is.
  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Points to plan documents describing the exclusion.
  • CO-96 (Non-covered charge(s).): Non-covered charge in general, used with a remark code explaining why.
  • PR-204 (This service/equipment/drug is not covered under the patient's current benefit plan): Service not covered under the current benefit plan.
  • CO-185 (The rendering provider is not eligible to perform the service billed.): The rendering provider isn't eligible to perform the service billed.
  • CO-170 (Payment is denied when performed/billed by this type of provider.): Denied when performed or billed by this type of provider.

CO-53 FAQ

Who counts as an immediate relative?

Definitions vary by payer. Medicare's rule covers a spouse, natural or adoptive parents, children, and siblings, step-relatives, in-laws, grandparents and grandchildren, and spouses of grandparents and grandchildren. Check each plan's definition.

Does the rule apply if a relative works in my practice but didn't treat the patient?

Medicare's exclusion is based on the relationship between the patient and the provider who furnished or ordered the service, including certain supervising and billing relationships. Details are technical, so check the payer's rules for your situation.

Can I appeal CO-53?

Only if the relationship was reported in error, for example the payer matched the wrong provider or household. If the relationship is real and the plan excludes it, an appeal is unlikely to succeed.

Can a family member bill for care if they are employed by an agency?

It depends on the payer. Some programs, particularly certain Medicaid home care programs, allow paid family caregivers under specific rules. Check the program's requirements.