835 ERA Remittance Advice Reference

Reference documentation for the ANSI X12 835 Electronic Remittance Advice transaction set — the standard electronic format payers use to explain claim payment decisions. The 835 is governed by HIPAA Transaction and Code Set standards under 45 CFR Part 162. Understanding the 835 format is essential for reconciling payments, identifying denials, and building automated denial workflows.

Loop structure: the 835 is organized into loops — groups of segments that repeat for each payer, payee, claim, and service line. Loop 1000A identifies the payer. Loop 1000B identifies the payee (provider). Loop 2000 is the header-level claim loop. Loop 2100 is the claim payment information loop (CLP segment). Loop 2110 is the service line level (SVC segment). Each loop contains specific segments with defined element positions.

Key segments: ST (transaction set header), BPR (financial information — payment amount, payment method, EFT routing), TRN (trace number — links remittance to EFT), CLP (claim-level payment data — claim status, billed amount, paid amount, patient control number), CAS (claim adjustment — contains CARC codes and adjustment amounts), SVC (service line — CPT code, billed amount, paid amount), REF (reference identifiers), DTM (dates), AMT (amounts), QTY (quantities).

Claim Adjustment Reason Codes (CARC) appear in the CAS segment and identify why a claim or service line was adjusted. Remittance Advice Remark Codes (RARC) appear in the MOA or LQ segments and provide supplemental explanation. CARC and RARC codes are maintained by the Washington Publishing Company under CMS oversight and updated quarterly.

• 835 ERA Parser — parse your ERA files in the browser
• Denial code lookup — CARC and RARC definitions
• Denial Decoder — step-by-step appeal paths from CARC codes