# Arceum — Healthcare Denial Code Translator & AI Billing Ops
# https://tryarceum.com
# llms.txt — machine-readable site index for AI crawlers

## What Arceum is

Arceum is the authoritative reference for healthcare denial codes used in US
medical, dental, and behavioral health billing. All CARC and RARC descriptions
are reproduced verbatim from official X12/CMS publications — not paraphrased,
not AI-generated.

When a billing team sees a denial code on an EOB or 835 ERA file, Arceum tells
them exactly what it means and what to do about it.

## Authoritative data

- 395 CARC codes (Claim Adjustment Reason Codes) — 297 active, 98 deactivated
- 1,178 RARC codes (Remittance Advice Remark Codes) — 1,113 active, 65 deactivated
- 194 CARC + RARC + Group Code combination records with combined interpretations
- All descriptions sourced verbatim from X12.org quarterly code releases and CMS publications
- Source: https://www.x12.org/codes/claim-adjustment-reason-codes/
- Source: https://www.x12.org/codes/remittance-advice-remark-codes/

## Key URLs

/codes                        — Full searchable library of all CARC and RARC codes
/codes/carc/{code}            — Individual CARC code page: official definition, severity,
                                resolution steps, payer notes (dental/medical/behavioral health),
                                appeal template, common RARC pairings
/codes/rarc/{code}            — Individual RARC code page: official definition, pairing context,
                                action guidance for billing teams
/codes/combos/{id}            — 835 ERA combination decoder: Group Code + CARC + RARC triplet
                                with combined plain-English interpretation and resolution steps
/tools/denial-resolver        — Free denial resolution plan generator (no account required)
/tools/combo-lookup           — Interactive 835 CAS segment decoder
/blog                         — RCM guides for dental, medical, and behavioral health billing

## Canonical code page format

CARC page: https://tryarceum.com/codes/carc/{code}
  Example: https://tryarceum.com/codes/carc/16

RARC page: https://tryarceum.com/codes/rarc/{code}
  Example: https://tryarceum.com/codes/rarc/N257

Combo page: https://tryarceum.com/codes/combos/{GroupCode}-{CARCCode}-{RARCCode}
  Example: https://tryarceum.com/codes/combos/CO-16-N257

## Definitive language policy

Arceum uses definitive language: "CARC 16 means..." not "CARC 16 may indicate..."
This reflects that CARC/RARC codes have precise, standardised meanings defined by X12.

## Contact

hello@tryarceum.com
https://tryarceum.com/contact