X12 835 Remittance Advice Explained

The X12 835, often called an ERA (Electronic Remittance Advice), is how a health insurance payer tells a provider exactly what was paid, adjusted, or denied on a submitted claim — the response half of the claim/payment cycle that begins with an 837 Healthcare Claim.

What Is an X12 835 File?

The 835 Healthcare Claim Payment/Remittance Advice transaction set explains, line by line, how a payer adjudicated one or more claims: the amount billed, the amount allowed, the amount actually paid, and standardized reason codes for any reduction or denial. Providers' billing staff use it to post payments and identify which claims need appeal or resubmission.

Key Segments in an 835

• BPR (Financial Information) — the total payment amount and payment method (EFT, check).
• CLP (Claim Payment Information) — one per claim: claim ID, billed amount, and paid amount.
• CAS (Claim Adjustment) — reason codes (CARC) and amounts explaining any reduction from the billed amount.
• SVC (Service Payment Information) — line-level detail matching the original claim's service lines.
• PLB (Provider Level Adjustment) — adjustments applied across the whole provider rather than one claim (e.g. a prior overpayment recovery).

Understanding CARC and RARC Codes

The CAS segment references standardized Claim Adjustment Reason Codes (CARC) — for example, code 45 means "charge exceeds fee schedule/maximum allowable amount." Some payers add Remittance Advice Remark Codes (RARC) for further detail. These codes are maintained by a national code-set committee independent of any single payer, which is why they mean the same thing across every insurer's 835 files.

A Worked Example

BPR*C*435.00*C*ACH~
CLP*CLAIM0001*1*250.00*200.00**MC~
CAS*CO*45*50.00~
SVC*HC:99213*150.00*120.00~

Read left to right: a total payment of $435.00 by ACH, for claim CLAIM0001 billed at $250.00 and paid $200.00, with a $50.00 contractual reduction (CARC 45) explaining the difference.

Converting an 835 to a Spreadsheet

To turn an 835 file into a readable table, use Convert X12 835 to CSV or Convert X12 835 to Excel — every BPR, CLP, CAS, SVC, and PLB segment is labeled automatically, and CARC codes appear alongside their raw values.

Frequently Asked Questions