RecoveAR · AI AR Recovery

From 835 to Appeal: CARC/RARC-Driven Denial Routing on Autopilot

The remittance already tells you why the claim was cut and what to do next. The problem is that the answer is buried in a machine-readable file no human wants to read. RecoveAR reads it for you, and routes every denial the same day it lands.

⚡ Short answer: Every CARC and RARC in the 835 maps to exactly one next action. RecoveAR parses the ERA, reads the adjustment codes at the service-line level, and drops each denial into the right lane, appeal, rebill, patient bill, or write-off, with the clock already running against the payer's filing deadline.

3×CARC/RARC lists are refreshed a year, in March, July, and NovemberX12 / CMS code committee

120 daysTo file a Medicare redetermination from the date on the remittanceCMS Claims Proc. Manual Ch. 29

CORE 360The CAQH CORE rule forcing uniform CARC/RARC use across payersCAQH CORE Phase III

005010The X12N 835 version every ERA in the U.S. is transmitted inASC X12N 005010X221A1

The premise

One denial, followed end to end

Instead of another list of best practices, follow a single denied line, an archetype PT claim for a commercial payer, from the moment the 835 posts to the moment RecoveAR files the appeal. Every step is a real code, a real rule, and a real deadline.

T+0h The 835 posts

The remittance arrives, not a letter

The payer returns an X12 835 Health Care Claim Payment/Advice (version 005010X221A1). It is the electronic remittance advice, the ERA. Inside, the CLP segment carries the claim-level status and the CAS segments carry every dollar that moved off the billed charge, each one tagged with a group code and a reason code.

CLP*PATACCT*22*240.00*0.00*...
CAS*CO*197*240.00 ← contractual, denied: no authorization

A person would need to open the file, find the service line, and decode CO*197. RecoveAR does it on ingestion, in bulk, across every ERA in the batch.

T+0h The read

Group code first, then the reason

The group code decides who owns the balance. The CARC decides why. The RARC adds the detail that tells you whether it is worth fighting.

CO · Contractual Obligation PR · Patient Responsibility OA · Other Adjustment PI · Payer Initiated

Our line came back CO 197, "precertification/authorization/notification absent." Paired with a RARC like N54 or a remark pointing at the missing auth number, this is not a write-off. It is a workable denial with a paper trail, exactly the kind of line that leaks to adjustment when a caller is buried.

CARC 197 · auth absent RARC N54 · claim info discrepancy

T+0h The fork

Routing is deterministic, not a guess

RecoveAR does not "score" the denial and hope. Each CARC/RARC combination maps to one lane. That mapping is anchored to the CAQH CORE 360 rule, which forces payers to use the standard code combinations consistently, so the same code means the same thing no matter who sent the 835.

Our line lands in the appeal lane: the authorization exists in the record, the payer says it does not, that discrepancy is exactly what an appeal is for. A pure contractual write-off (CO 45, charge exceeds fee schedule) would never enter this lane. Neither would a clean patient-responsibility code.

T+1h The clock

The deadline starts the second it routes

The moment a denial enters the appeal lane, RecoveAR stamps it against the correct filing window, because the wrong deadline is the same as no appeal. The window depends on the payer:

Payer / level	File within	Decision by	Source
Medicare redetermination (Level 1, MAC)	120 days	60 days	CMS Claims Proc. Manual Ch. 29
Medicare reconsideration (Level 2, QIC)	180 days	60 days	CMS Claims Proc. Manual Ch. 29
Medicare ALJ hearing (Level 3, OMHA)	60 days	90 days*	42 CFR 405.1002 / AIC threshold
Commercial / Medicaid MCO	Per contract	Per contract	Payer provider manual

*The ALJ 90-day standard applies once the amount-in-controversy threshold is met and the level is properly reached. RecoveAR carries the payer-specific commercial windows from each contract's provider manual, so a 90-day plan never gets treated like a 120-day one.

T+1h The assembly

The appeal builds itself from the 835

Because RecoveAR already parsed the CLP and CAS segments, it knows the claim number, the billed amount, the denied line, and the exact CARC/RARC being contested. It pulls the matching authorization from the record and assembles a redetermination-style packet: the specific denial reason answered directly, not a generic "please reconsider."

The denied service line, the group and reason codes verbatim from the remittance, and the supporting authorization travel together, so the person who reviews and files is reviewing a finished argument, not starting one.

Claim ID pulled from CLP01 Denied $ from CAS amount Reason quoted: CO 197 Auth attached from record

T+1 day The filing

Filed, tracked, and closed the loop

The appeal goes out inside its filing window, with the deadline, the payer, and the contested codes logged. When the next 835 posts, RecoveAR reads it the same way, and either books the recovery or advances the denial to the next appeal level automatically. The line that would have quietly aged past timely-filing instead comes back as cash.

That is the whole point of AI AR recovery: not a smarter dashboard, but the boring, deadline-bound work of turning remittance codes into filed appeals, done at the speed the ERA arrives instead of the speed a caller can get to it.

Appeal or adjust

The codes decide the lane

The difference between a recovered dollar and a written-off one is usually a single code read correctly. A sample of common CARCs and where they route, so you can see the logic RecoveAR runs on every line.

CARC	Means	Group	Lane
197	Precert / authorization absent	CO	Appeal (if auth exists)
50	Not deemed medically necessary	CO	Appeal w/ docs
16	Claim lacks information / submission error	CO	Correct & rebill
11	Diagnosis inconsistent with procedure	CO	Correct & rebill
29	Time limit for filing expired	CO	Appeal (proof of timely)
45	Charge exceeds fee schedule	CO	Contractual write-off
1 / 2 / 3	Deductible / coinsurance / copay	PR	Patient statement

Reason-code meanings above follow the X12 Claim Adjustment Reason Code and Remittance Advice Remark Code lists maintained under the X12 code committee and CMS. Routing outcomes are examples; the workable-versus-contractual call always depends on what the underlying record supports.

Standards, not shortcuts

What this is built on

RecoveAR's routing is only as trustworthy as the standards underneath it. Every one of these is real, current, and cited by name.

ASC X12N 005010X221A1

X12 835 Remittance Advice

The HIPAA-mandated electronic remittance format. RecoveAR reads CLP claim status and CAS adjustment segments directly, at the service-line level.

X12 & CMS code committee

CARC / RARC code lists

Claim Adjustment Reason Codes and Remittance Advice Remark Codes, updated three times a year. RecoveAR's routing map tracks each release so retired codes never misroute.

CAQH CORE Phase III

CORE 360 operating rule

The Uniform Use of CARC/RARC rule that forces payers to apply standard code combinations consistently, the reason deterministic routing works across payers.

CMS Manual Ch. 29 / 42 CFR 405

Medicare appeal timelines

Redetermination at 120 days, reconsideration at 180, each with its own decision window. RecoveAR stamps every routed denial against the correct clock.

Stop reading 835s by hand.

If your team is decoding remittance codes one claim at a time, denials are aging past their filing windows while they work. RecoveAR reads every ERA on arrival and routes each denial to a filed appeal, so the recoverable dollars actually come back. Let us show you your own denials routed.

Book a RecoveAR walkthrough → Talk to an AR recovery specialist

Sources referenced: ASC X12N 835 Health Care Claim Payment/Advice (005010X221A1); X12 Claim Adjustment Reason Code and Remittance Advice Remark Code lists (X12 / CMS code committee, updated March, July, November); CAQH CORE 360 Uniform Use of CARC and RARC (CORE Rule, Phase III); CMS Medicare Claims Processing Manual, Chapter 29 (Appeals of Claims Decisions) and 42 CFR Part 405 Subpart I. Claim scenarios use non-client archetypes; no real patient, claim, or client data is shown. Routing outcomes are illustrative and depend on the supporting record.