What are RARCs, the remark codes on a remittance?
Remittance advice remark codes (RARCs) are the M, MA, and N codes on a remittance that give more detail about an adjustment than its claim adjustment reason code does. CARC 16 says information is missing or wrong, and a remark code such as M22 says the problem is the number of miles. Remark codes that begin with "Alert:" only pass along information.
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A remark code narrows down the reason
Every adjustment on a remittance carries a claim adjustment reason code (CARC) that says why the amount changed. The reason code is often too broad to act on. The remittance advice remark code (RARC) supplies the specifics: which field, which rule, or which document.
X12, which publishes the list, sorts remark codes into two kinds:
| Kind | How to spot it | What it does |
|---|---|---|
| Supplemental | Plain wording with no “Alert:”. Most remark codes are this kind | Explains an adjustment that already has a reason code |
| Informational | Text starts with “Alert:” | Shares processing information. Never tied to a specific adjustment |
Some reason codes are too general to use alone. X12 requires at least one non-alert remark code with CARC 16 (information missing, or a billing error), 96 (non-covered charge), 226 (requested information not provided), 252 (an attachment is needed), and A1 (claim denied). If a remittance shows one of those with no remark code, ask the payer for the detail before you rework the claim.
Where remark codes sit on an 835
On an electronic remittance, a remark code that applies to one service line goes in the LQ segment of that line. A remark code that applies to the whole claim goes in the claim’s MOA segment (MIA on inpatient claims). The implementation guide allows up to 5 claim-level and 99 line-level remark codes, though CMS notes that system limits can keep a payer from reporting that many. Our guide to NEMT remittance advice walks through the rest of the 835.
What the M, MA, and N prefixes mean
The prefix is history, not a category. When Medicare started using remark codes, M codes applied to service lines and MA codes to whole claims. A 2001 Medicare program memo ended that split: any remark code can now be reported at either level if its wording fits. The memo kept the old numbers to avoid confusing providers and said new codes would start with N, which also sets remark codes apart from reason codes at a glance.
CMS still maintains the list, and any health plan may use it. It changes three times a year, around March 1, July 1, and November 1. The X12 list shows a start date for each code and can be filtered to current codes or codes set to be deactivated.
Remark codes that fit transportation claims
Plenty of remark codes read as if they were written for NEMT. The wording below is condensed from the official list.
| RARC | What it says | Where to look first |
|---|---|---|
| M22 | Miles traveled missing, incomplete, or invalid | The units on your mileage line, such as S0209 |
| N53 | Pickup address missing, incomplete, or invalid | Where the payer wants trip addresses. Arizona fee-for-service has wanted both addresses of every trip on the claim since November 1, 2022 |
| M62 | Treatment authorization code missing, incomplete, or invalid | The trip or prior authorization number you entered |
| N54 | Claim does not match the authorized services | Level of service, date, and miles against the authorization |
| N157 | Transportation to or from this destination is not covered | Whether the destination qualifies under the rider’s benefit |
| N255 | Billing provider taxonomy missing, incomplete, or invalid | The taxonomy code from your enrollment |
| N767 | The state requires the provider to be enrolled in the member’s Medicaid program before the claim is processed | Your Medicaid enrollment with that state |
| N904 | The transportation vendor is responsible for this claim | Whether the trip belongs to the plan’s broker or ride vendor |
N904 is recent: X12 lists its start date as July 1, 2024. N767 shows up in practice too. Ohio tells its managed care plans to deny claims from providers who refuse to enroll with the state using CARC 226 and RARC N767, and only after 180 days of outreach.
Reading a pair, with examples
Read the reason code for the category and the remark code for the fix. Two examples, using codes from the official lists:
- CO-16 with M22 on a mileage line. The claim lacked information (16), and the missing piece is the mileage (M22). Correct the units and follow the payer’s rules for sending the line back.
- CO-16 with N53. Same category, different fix: the pickup address is missing or unreadable, so the address is what needs correcting.
For common situations, payers do not pick pairs freely. The CAQH CORE rule on uniform use of these codes sets a maximum list of reason, remark, and group code combinations for four business scenarios, and the second scenario covers missing or invalid data on the submitted claim. The point is that the same problem should produce the same codes at every payer. When a denial holds up after you fix the flagged field, the appeals guide covers the next step, and the claim rejection entry covers claims that were stopped before processing.
Frequently asked questions
- Do M and MA remark codes only apply to Medicare?
- No. The letters come from Medicare's early use of remark codes, when M codes were for service lines and MA codes were for whole claims. A 2001 Medicare program memo dropped those categories, kept the old numbers, and reworded the messages so any payer could use them. Every remark code added after 2001 starts with N. Brokers, health plans, and state Medicaid programs that send 835s draw on the same list.
- How often does the remark code list change?
- Three times a year. CMS, which maintains the list, updates it on or around March 1, July 1, and November 1, in step with the reason code list. Codes are added, reworded, or given a stop date, and the X12 list shows each code's start date and any later changes. Check a code against the current list before you act on an old explanation of it.
- What does it mean when a remittance shows a remark code with no reason code?
- It is almost certainly an alert. Informational remark codes start with the word "Alert:" and CMS lets them be reported without a group code or reason code. They pass along information, such as appeal instructions, and under X12's definition an alert is never attached to one particular adjustment. Supplemental remark codes, by contrast, always explain an adjustment that has its own reason code.
