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The 835 (formally the X12N 835 Health Care Claim Payment/Advice, colloquially the ERA) is the file a payer sends to explain a payment. One file tells you, claim by claim and line by line, what was paid, reduced, or denied, and why. HIPAA designates the 835 as the standard electronic remittance format (45 C.F.R. § 162.1602). Every covered payer can produce one. If a major payer sends you paper EOBs, that’s an enrollment gap, not a technical limit. See Enroll in EFT and ERA.

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Anatomy

One 835 = one payment. A single $14,306.22 deposit might cover 40 claims. The parts worth knowing:
  • TRN links the file to the ACH deposit. When money and remittances won’t line up, match on TRN and BPR10. Full story: EFT reassociation.
  • CAS accounts for every dollar between billed and paid, each with a group code (CO contractual, PR patient responsibility) and a CARC. The math must balance or posting software rejects the file.
  • PLB is where mysterious shortfalls live. A deposit $2,400 short of its claims usually has a PLB recouping an old overpayment.

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Why owners should care

Automation lives on the 835. Payers on ERA post automatically; payers on paper mean manual keying at real labor cost. Denials are data. CAS segments are a structured record of every dollar not collected and the stated reason. Aggregate them and fix the top causes. It’s your audit trail. In an underpayment dispute, the 835 is the evidence.

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Common failure modes

File arrives but money doesn’t, or vice versa: reassociation problem. Payment by virtual card falls short of the 835 amount: card fees, see ERA vs. EOB. 835 never arrives for a payer: ERA enrollment gap, see the directory. Paper check with EOB, no 835 at all: the paper problem.
Lemma aside: Lemma parses 835s and scanned EOBs, reassociates them with deposits automatically, and can generate 835s from paper EOBs to feed your EHR (docs).