CO-33: insured has no dependent coverage.

What X12 says CARC 33 means

Insured has no dependent coverage.

CARC 33 · Start 01/01/1995, last modified 09/30/2007.

In plain terms: The payer says the insured's coverage does not include dependents.

What it means on a remittance

Where CARC 32 questions the patient's status as a dependent, CARC 33 says the insured's policy has no dependent coverage at all. It points at the coverage tier on the policy.

Typical causes

• The subscriber enrolled in an individual-only tier.
• The claim was billed under the wrong subscriber, for example the other parent.
• The patient has coverage under a different policy that is primary or the only one that covers dependents.
• A dependent-coverage change had not reached the payer's file when the claim was processed.

These are common billing patterns, not a diagnosis of your claim. The remittance and the payer's policy decide.

What to check

1. Run eligibility for the date of service and note the coverage tier.
2. Ask the patient whether another parent, spouse or plan covers them.
3. Confirm the subscriber ID and name on the claim.
4. Check the remark code for any further explanation.

Correct, resubmit or appeal

If another plan covers the patient, bill that plan. If the tier changed recently, ask the payer to reprocess once the file is updated. If no coverage applies, your policies and contract decide how the balance is handled.

Medicare dates that apply

A Medicare redetermination request must be filed within 120 calendar days from the date a party receives the notice of the initial determination; receipt is presumed 5 calendar days after the notice date unless there is evidence to the contrary (42 CFR 405.942(a)), and a late request can be considered for good cause (405.942(b)). Other payers set their own appeal windows in the contract or plan documents, so read the notice for the date. The tool above runs the date math.

Related codes

X12 does not publish a table that pairs each code with remark codes; the payer picks the remark code and prints it beside the CARC on the same remittance line. These X12 remark codes carry wording that speaks to this topic:

• N30 — Patient ineligible for this service.

Other codes: CARC 32 (not an eligible dependent), RARC N30 and the full lookup.

Worked example (hypothetical)

A spouse's claim returns CO-33. Eligibility shows the employee elected employee-only coverage. The spouse has coverage under her own employer. The biller bills that plan as primary.

Sources

• X12: Claim Adjustment Reason Codes — code text, usage notes and dates (list dated 10/30/2026, retrieved 2026-11-02)
• X12: Remittance Advice Remark Codes — remark code text (retrieved 2026-11-02)
• 42 CFR 405.942 — eCFR, current through 2026-10-29 (retrieved 2026-11-02)

Code descriptions are X12 copyrighted material, quoted here only for the codes on this page and linked to the owner. For the full lists, use X12. The X12 text and the Medicare rule above were read from these pages on November 2, 2026. Causes, checks and examples are general billing practice written for this page, not X12 content. Payers revise code lists, contracts and policies, so confirm anything that affects a claim or a deadline with the payer.