How to Read an 835

The 835 is the X12 Health Care Claim Payment/Advice transaction — the electronic remittance advice, or ERA, that a payer sends a provider after it decides one or more claims. It is the provider-facing record of an adjudication. A single 835 usually reports a batch of claims rather than one, and it is the document the rest of the Payments & Posting section is about posting, proving, and following up. How it differs from the patient's Explanation of Benefits is EOB vs. ERA's subject; this article is about the 835 itself.

Its job is to be read by a machine. The 835 carries claim- and line-level detail in a structured form so a billing system can match each payment to the right claim, apply the adjustment, leave the correct patient balance, and flag anything that did not pay as expected. That mechanical step is payment posting, and how it works is How Payment Posting Works.

Every 835 is built in three tiers. Reading one is mostly a matter of knowing which tier you are looking at, because the same kind of figure means different things depending on where it sits.

The header

Appears once, at the top. Who paid, who was paid, the total amount, how the money moved, and the trace number that ties the remittance to the deposit.

The claim and service-line detail

The body, repeating once per claim and, within each claim, once per service line. The result of each claim and each line — charged, paid, adjusted, and assigned to the patient.

The provider-level summary

Appears once, at the end. Adjustments that act on the provider's account as a whole rather than on any single claim.

The distinction earns its keep at the two ends. An amount inside a claim is a statement about that claim; an amount in the summary is a statement about the account. Confusing the two is how a recovery of last month's overpayment gets read as this month's claim being underpaid — the same number, on the wrong level.

The financial-information segment — BPR — carries the payment itself: the total amount, whether it moved by EFT or by check, or whether the 835 carries no payment at all and is data only, together with the effective date of the transfer. It is the one place the whole remittance's money is stated as a single figure.

Two identification loops (N1) name the payer that adjudicated the claims and the payee that received the funds. For a provider reconciling a deposit, these answer the first question the bank cannot: which plan this money is from.

The trace segment — TRN — carries a reassociation trace number. The same number rides on the EFT deposit, so the remittance and the money can be paired mechanically rather than by hunting for a deposit that looks about the right size. Using that trace to match the two is the heart of Payment Reconciliation, which is where the pairing — and what to do when it fails — belongs.

The body of the 835 repeats once per claim. Each claim opens with a claim-payment segment — CLP — that carries the practice's own claim number, the payer's internal control number for the claim, the total charge submitted, the amount paid, the patient responsibility transferred back, and a status code.

The status code says what became of the claim in broad terms: processed and paid — as the primary, secondary, or tertiary payer — or denied, or reversed, or forwarded on to the next payer as a crossover. It is the fastest read on the remittance: before any dollar figure, it says whether this claim paid, refused, or moved.

Beneath the claim, a service-payment segment — SVC — repeats once per service line: the procedure code and any modifiers, the charge submitted for that line, the amount paid on it, and the units. This line detail is what lets each service be traced from what was billed to what was paid, and it is what a secondary claim needs to carry forward. What those figures mean once you have them — how the allowed amount splits into a write-off, a payment, and a patient share — is From Billed Charge to Collected Dollar.

Whenever a paid amount differs from what was charged, the 835 says why in an adjustment segment — CAS. Each adjustment is three things together: a group code, a reason code, and an amount, and a single segment can carry several. A CAS can appear at the claim level and on an individual service line, because a reduction can apply to either.

The group code is the part that decides who bears the amount — a contractual adjustment the provider writes off, or an amount that is the patient's responsibility — and posting the wrong one bills a patient for money they do not owe. What each reason code says, and how the group codes divide responsibility, is read the same way on any remittance and is the subject of Reading a Denial, the canonical home for it. The reason codes — the CARC and its supplemental RARC — are national, standardized code sets whose text is licensed and revised on a published schedule, so a code is identified by its number and read against the current list rather than from memory.

At the very end of the 835, a provider-level adjustment segment — PLB — reports money that is not tied to any single claim. It acts on the provider's account as a whole. A prior overpayment being recovered as an offset or recoupment, interest a payer owes, an incentive or penalty, or a balance carried forward to a future remittance all appear here rather than inside a claim.

This is the usual answer to why the deposit does not equal the sum of the claim payments. The PLB moves money above the claim level: a recoupment recovering last month's overpayment reduces today's deposit without touching a single claim on today's remittance. That is invisible unless the summary is read — the claims all appear to have paid in full while the check came up short. How that offset is worked and posted is Underpayments and Overpayments's subject; here the point is only that the summary is where to find it.

The 835 can also undo a payment it made before. A reversal restates the original claim as negative amounts that back the earlier posting out, and re-reports the corrected result alongside it — so a single file can net to a different figure than its individual claims first suggest. Read together with the PLB, it is the mechanism by which an 835 both explains a payment and quietly recovers an old one.

Everything the 835 records becomes what the practice believes afterward, including the totals its metrics are measured from — the net collection rate is computed from the allowed amounts, adjustments, and payments the 835 reports. Reading it correctly, at every level, is the difference between a figure the practice can trust and a confidently wrong one.