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CO-178 Denial Code: Medicaid Spend-Down Not Met

CO-178 means the patient has not met the spend-down requirement. In medically needy Medicaid programs, patients must incur a certain amount of medical expenses before coverage begins for the period. Until the spend-down is met, the program won't pay.

Quick facts

Code
CO-178 (CARC 178)
Status
Active In use since June 30, 2005; last modified September 30, 2007.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The payer isn't paying yet. Whether you may bill the patient depends on state Medicaid rules, since incurred expenses often count toward the spend-down.
  • PR (Patient Responsibility): The payer indicates the amount is the patient's responsibility and may count toward the spend-down obligation.
Official description
Patient has not met the required spend down requirements.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-178 means

CARC 178 reads “Patient has not met the required spend down requirements.” It is used almost entirely by Medicaid programs with medically needy or spend-down eligibility. The patient is enrolled in a conditional way: coverage for a period starts only after they’ve incurred enough medical expenses to reduce their countable income to the program’s limit.

Claims for dates before the spend-down is met are denied with CO-178. Those same charges are often what the patient uses to meet the spend-down.

Example: a patient has a monthly spend-down amount. Early in the month, a visit is billed to Medicaid before the patient has incurred the full amount. The claim is denied CO-178. Once the patient submits bills showing the spend-down is met, later services that month may be covered.

Common causes

  • Spend-down not yet met for the period when the service occurred.
  • Patient hasn’t reported expenses to the state agency.
  • Claims submitted before the state updates eligibility after the spend-down is met.
  • Period mismatch, where the service date falls in a different spend-down period than expected.

How to fix it

  1. Check eligibility for the exact date of service and ask whether the spend-down status is met, partially met, or pending.
  2. Provide the patient with an itemized bill so they can submit it to the state toward the spend-down.
  3. Resubmit or request reprocessing once the state shows the spend-down met, following the state’s instructions.
  4. Collect from the patient only as your state Medicaid program allows for the spend-down portion.
  5. Keep records of claim submission dates, since spend-down resolution can take time relative to filing limits.

How to prevent it

  • Identify spend-down patients at registration from the eligibility response.
  • Hold non-urgent claims until the spend-down status for the period is known, keeping filing limits in mind.
  • Explain the process to patients so they report expenses promptly.
  • Coordinate with the state agency or eligibility worker when status is unclear. See eligibility and COB denials.

Specialty notes

Behavioral health, long-term care, and home health providers serving medically needy populations see this code more than others because their patients are more likely to be enrolled through spend-down.

Remark codes that may appear with CO-178

  • N30 (Patient ineligible for this service.): The patient is not eligible for the service at the time processed.
  • CO-177 (Patient has not met the required eligibility requirements.): A general eligibility requirement was not met.
  • CO-179 (Patient has not met the required waiting requirements.): A waiting period has not ended.
  • PR-1 (Deductible Amount): A deductible, which works differently from spend-down but is also patient cost-sharing.
  • PR-27 (Expenses incurred after coverage terminated.): Coverage terminated before the date of service.

CO-178 FAQ

What is a Medicaid spend-down?

Some states let people with income above the Medicaid limit qualify as medically needy once their medical expenses reduce their countable income to the limit. That required amount is the spend-down, often calculated per month or longer period.

Should I bill the patient for a CO-178 claim?

Your bill may be the expense that helps the patient meet spend-down. Give the patient the documentation they need to report it, and follow your state's Medicaid rules on what you may collect.

Can the claim be paid later?

Often yes. Once the state records that the spend-down is met, Medicaid may cover claims for the remainder of the period. Ask the state or plan whether to resubmit and how.