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N749 Remark Code: Missing Blood Gas Report

N749 means the payer needed a blood gas report to process this claim and did not receive one. It is most often seen on home oxygen claims, where arterial blood gas or oxygen saturation results show whether the patient qualifies.

Quick facts

Code
N749 (RARC N749)
Status
Active In use since March 1, 2015.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The supplier or provider carries the denied amount until the qualifying test report is supplied.
Official description
Missing Blood Gas Report.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N749 means

For home oxygen and some respiratory services, coverage depends on documented low blood oxygen levels. The blood gas report provides that proof. N749 says the payer found no such report for the claim and could not confirm the patient qualified.

The remark usually accompanies CARC 252 or CARC 272. It is most familiar to DME suppliers, but any provider billing a service whose coverage depends on oxygen testing can receive it.

Common causes

  • The supplier set up oxygen based on an order, without collecting the test results.
  • The qualifying test was done in a hospital or physician office and never sent to the supplier.
  • The report was submitted for the initial claim but not for a later recertification period.
  • Records sent to the payer were not tied to the claim.

How to fix it

  1. Obtain the qualifying test report from the hospital, lab, or physician office that performed it.
  2. Check the date, testing conditions (for example at rest, during exercise, or during sleep), and results against the payer’s oxygen policy.
  3. Submit the report with claim identifiers through the payer’s documentation or reconsideration process.
  4. If no qualifying test exists, the ordering physician may need to arrange one. The claim may not be payable until then.

How to prevent it

Collect and review the qualifying test before delivering oxygen equipment, and keep it with the certification. Recertification periods can require new testing, so track those dates.

Codes that may appear with N749

  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): Documentation is required to adjudicate; here, the blood gas report.
  • CO-272 (Coverage/program guidelines were not met.): The payer could not confirm oxygen coverage criteria without the test results.
  • CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): Some payers deny as not medically necessary when no qualifying test is on file.
  • N750 (Incomplete/invalid Blood Gas Report.): A blood gas report was received but was incomplete or invalid.
  • M8 (We do not accept blood gas tests results when the test was conducted by a medical supplier or taken while the patient is on oxygen.): The blood gas test was not acceptable because of who performed it or the patient's oxygen status at the time.
  • M19 (Missing oxygen certification/re-certification.): The oxygen certification or recertification is missing.
  • N328 (Missing/incomplete/invalid Oxygen Saturation Test date.): The oxygen saturation test date is missing or invalid.

N749 FAQ

What counts as a blood gas report?

Typically an arterial blood gas result or, where the payer accepts it, an oxygen saturation test result, with the test date, conditions of testing, and the name of the qualified provider or lab that performed it.

Can the oxygen supplier perform the qualifying test?

Many payers, including Medicare, restrict suppliers from performing the qualifying test. Check the payer's policy, since a supplier-performed test may be rejected.

What if the test was done during a hospital stay?

Payers often accept tests from a recent inpatient stay if they meet timing and condition rules. Send the report along with the testing conditions.