Skip to main content

MA33 Remark Code: Invalid Non-Covered Days

MA33 means the number of non-covered days during the billing period is missing, incomplete, or invalid. When part of a stay is not covered, the payer needs an accurate non-covered day count to separate those days from the covered ones.

Quick facts

Code
MA33 (RARC MA33)
Status
Active In use since January 1, 1997; last modified March 1, 2022.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The facility must correct the reporting. Non-covered days are billable to the patient only when coverage and notice rules allow it.
Official description
Missing/incomplete/invalid non-covered days during the billing period.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What MA33 means

Not every day of an institutional stay is always covered. When some are not, the claim has to say how many, so the payer can pay the covered portion and correctly treat the rest. MA33 says that non-covered day count was absent, did not match the rest of the claim, or was reported where it made no sense.

It commonly shows up alongside non-covered charges or occurrence spans that do not agree with the day total.

Common causes

  • Non-covered charges appear on the claim, but no non-covered day count was reported.
  • Non-covered days plus covered days do not equal the days in the statement period.
  • The occurrence span for non-covered dates does not match the number of days reported.
  • Leave-of-absence days were reported as non-covered when the payer expects a different method.

How to fix it

  1. Identify the non-covered dates from the medical record and utilisation review notes.
  2. Report the day count with the correct value code and any required occurrence span.
  3. Reconcile totals so covered and non-covered days match the statement period and accommodation units.
  4. Resubmit the corrected claim through the payer’s adjustment process if it was already processed.

How to prevent it

Tie non-covered day reporting to your utilisation review decisions so the billing team receives exact dates. Checking these relationships before submission with a Claims Validator reduces back-and-forth with the payer.

Codes that may appear with MA33

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Required claim information is missing or invalid, with MA33 identifying non-covered days.
  • CO-78 (Non-Covered days/Room charge adjustment.): A non-covered days or room charge adjustment connected to the day count.
  • MA32 (Missing/incomplete/invalid number of covered days during the billing period.): The covered day count is missing or invalid.
  • MA34 (Missing/incomplete/invalid number of coinsurance days during the billing period.): Coinsurance days are missing or invalid.
  • MA35 (Missing/incomplete/invalid number of lifetime reserve days.): Lifetime reserve days are missing or invalid.

MA33 FAQ

What makes a day non-covered?

Examples include days after the patient no longer needed the level of care, days when benefits were exhausted, or days the patient chose to stay beyond medical need. The exact rules depend on the payer and benefit.

How are non-covered days reported?

On the UB-04 they are reported as a value code in form locators 39 to 41. Medicare uses value code 81 for non-covered days, often together with an occurrence span showing the dates.

Do non-covered days need an explanation?

Often yes. Payers may expect occurrence span codes, condition codes, or non-covered charges that explain why the days are not covered.