Skip to main content

N358 Remark Code: Decision Reviewable With Documentation

N358 is an alert that the claim decision can be reviewed if you send the additional documentation described in your contract or the patient's plan benefit documents. It points you toward a documentation-based review rather than a formal dispute.

Quick facts

Code
N358 (RARC N358)
Status
Active In use since November 18, 2005; last modified April 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The adjustment stands for now under the provider's contract. It can change if the payer reviews additional documentation and reverses the decision.
Official description
Alert: This decision may be reviewed if additional documentation as described in the contract or plan benefit documents is submitted.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N358 means

N358 doesn’t change the payment on its own. It tells you the payer is willing to look at the decision again if it receives the documentation described in the provider contract or the member’s benefit documents. In other words, the current outcome was reached without information that could matter.

It typically appears with a denial or reduction such as CARC 50, 150, or 252. The CARC tells you what was decided; N358 tells you that more records can reopen it.

What to do

  1. Read the CARC to understand what was denied or reduced.
  2. Find the section of your contract or the plan document that lists the documentation for this service, and note any time limit for submitting it.
  3. Pull the records that address the specific reason, rather than sending the entire chart.
  4. Submit them through the payer’s reconsideration or attachment process and reference the original claim number.
  5. Track the request. If the review is unfavorable, a formal appeal may still be available.

If this remark shows up often for the same service, add the documentation to the original claim going forward.

Codes that may appear with N358

  • CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): A medical necessity denial where records could change the outcome.
  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): Documentation is required to adjudicate, which N358 says can be supplied for review.
  • CO-150 (Payer deems the information submitted does not support this level of service.): The information submitted did not support the level of service billed.
  • N210 (Alert: You may appeal this decision.): A general alert that you may appeal the decision.
  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Directs you to plan benefit documents for restrictions on the service.
  • N187 (Alert: You may request a review in writing within the required time limits following receipt of this notice by following the instructions included…): Says you may request a review in writing within required time limits.

N358 FAQ

Is this an appeal?

It may be handled as a reconsideration or reopening rather than a formal appeal, depending on the payer. Check the contract or plan document the alert refers to.

What documentation should I send?

Whatever the contract or plan documents specify for this service, often clinical notes, test results, or a letter of medical necessity.

Is there a deadline for sending the documentation?

Usually, but it depends on the payer. The contract or plan document the alert refers to should state how long you have.