CO-30: eligibility, spend down, waiting or residency not met.

What X12 says CARC 30 means

Payment adjusted because the patient has not met the required eligibility, spend down, waiting, or residency requirements.

CARC 30 · Start 01/01/1995, stopped 02/01/2006 (retired).

In plain terms: The payment was adjusted because the patient had not met eligibility, spend down, waiting or residency requirements; X12 retired it in 2006.

What it means on a remittance

The X12 list marks CARC 30 as stopped on 02/01/2006, so a current code list no longer treats it as active. It still turns up in old remittances and search results, which is why it is explained here. The wording is about a patient who had not met a program or plan condition, such as a waiting period, a spend-down amount or a residency rule.

Typical causes

• A waiting period under the plan or program had not ended on the date of service.
• A spend-down amount, as in some state medical assistance programs, had not been met.
• A residency requirement was not met.
• The eligibility file did not yet show the patient as qualified.

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

What to check

1. Run an eligibility check for the date of service and read what the payer says about the missing condition.
2. Ask the patient whether an application or a spend-down is pending.
3. Check the remark code on the same line.
4. Check whether another payer covered the patient on that date.

Correct, resubmit or appeal

If the condition was met later, ask whether the payer will reprocess once eligibility is updated, and watch its filing limit. If it was not met, follow your policy for patient accounts. Use the payer’s own appeal steps if you believe the file is wrong.

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.

X12 remark codes whose wording speaks to this reason:

• N30 — Patient ineligible for this service.

Other codes: CARC 26 (expenses before coverage), RARC N30 (patient ineligible for this service), RARC N30 and the full lookup.

Worked example (hypothetical)

An old remittance for a clinic visit shows CO-30. The patient’s program approval was dated after the visit, so the biller checks whether the program backdates and holds the claim until the file updates.

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.