Glossary · Billing

Electronic Remittance Advice (ERA)

An Electronic Remittance Advice (ERA) is a standardized electronic document — formatted as an HIPAA X12 835 transaction — that a health plan sends to a provider explaining exactly how a claim was paid, partially paid, or denied, including all adjustment amounts and the reason codes behind them.

Verified May 8, 2026 · 6 sources ↓

Drawn from CMSEnCombinehealthAAPC

Definition

Source · Editorial summary grounded in 6 cited references ↓

When a payer processes a claim, it generates an ERA to communicate the financial outcome back to the billing team. The ERA details each service line, the amount billed, the amount allowed under contract, any contractual write-offs, patient-responsibility portions (copay, coinsurance, deductible), and the net payment issued. Adjustment amounts are explained through Claim Adjustment Reason Codes (CARCs) and Remittance Advice Remark Codes (RARCs), which are HIPAA-mandated standardized code sets maintained by X12. These codes replace payer-proprietary explanations, making it possible to interpret remittance data consistently across Medicare, Medicaid, and commercial plans.

An ERA travels alongside — but is distinct from — an Electronic Funds Transfer (EFT). The EFT moves the money through the ACH network; the ERA explains what that money covers. CMS and the Affordable Care Act required all health plans to support both EFT and ERA transactions upon provider request, with mandatory compliance beginning January 1, 2014. Providers must complete ERA enrollment with each payer (or clearinghouse) before electronic remittance files begin flowing.

In orthopedic billing, a single ERA may span dozens of service lines across a complex surgical claim — arthroplasty, hardware, anesthesia add-ons, therapy — each potentially carrying its own adjustment code. Billing staff triage each line: fully paid lines go straight to payment posting; partially paid lines require review of contractual adjustments versus payment errors; denied lines trigger correction or appeal workflows, often under tight payer-specific timelines.

Why it matters

Misreading or ignoring ERA adjustment codes directly costs orthopedic practices money. A CARC 4 (denial for late filing) requires an appeal with proof of timely submission; accepting it passively forfeits reimbursement permanently. A CARC 97 (bundled procedure) signals an NCCI edit was triggered, meaning the practice may have incorrectly unbundled CPT codes — an issue that, if systematic, creates audit exposure. For arthroplasty and spine cases with implant pass-through charges, a contractual adjustment that seems routine may actually reflect a payer applying the wrong fee schedule, and that difference is only recoverable if billing staff catch it in the ERA before the accounts-receivable clock runs out.

Common mistakes

Where people most often go wrong with this concept.

Source · Editorial brief grounded in cited references ↓

Auto-posting ERA payments without reviewing line-level CARCs first, which buries underpayments and uncontested denials in closed batches
Conflating a rejection (claim never adjudicated, returned by the clearinghouse) with a denial (claim adjudicated and refused by the payer) — each requires a completely different corrective path
Failing to complete ERA enrollment with a new payer before claims are submitted, causing the practice to receive paper EOBs that delay posting and reconciliation
Accepting a CARC 97 bundling adjustment on orthopedic add-on procedures without verifying whether the primary CPT code was actually billed on the same claim
Not mapping payer-proprietary remark codes to standard RARCs when a clearinghouse does not normalize them, leading to misclassified denial reasons in trend reports
Missing appeal deadlines because ERA review was deferred — most payers allow 90–180 days from the remittance date, not the date of service

Related codes

Codes commonly involved when this concept appears in practice.

Modifiers

59 Distinct procedural service XS Separate structure 26 Professional component

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What is the difference between an ERA and an EOB?

An ERA (X12 835) is a machine-readable electronic file sent from the payer to the provider's billing system. An EOB (Explanation of Benefits) is typically a human-readable document sent to the patient. Both explain claim adjudication, but ERAs are designed for automated payment posting and include standardized CARC and RARC codes; EOBs are written in plain language for patient comprehension.

02Do all payers have to send ERAs?

Under HIPAA Administrative Simplification and ACA operating rules effective January 1, 2014, health plans must conduct ERA transactions with providers upon request. However, the provider must first complete ERA enrollment — either directly with the payer or through a clearinghouse — before electronic remittance files begin transmitting.

03What is a CARC and why does it matter on an orthopedic ERA?

A Claim Adjustment Reason Code (CARC) is a standardized code that explains why a payer reduced or denied payment on a specific service line. In orthopedic billing, CARCs commonly signal bundling issues (CARC 97), medical necessity questions (CARC 50), or contractual adjustments. Reading the CARC correctly determines whether the next step is a write-off, a corrected claim, or a formal appeal.

04How long does a practice have to act on a denial found in an ERA?

Timelines vary by payer and plan type. Most commercial plans allow 90–180 days from the remittance date to file an appeal or corrected claim. Medicare timelines are set by the MAC. The remittance date printed in the ERA — not the date of service or claim submission — is typically the clock-start date, so prompt ERA review is essential.

05Can ERA data be used to identify systemic billing problems in an orthopedic practice?

Yes. Aggregating CARC and RARC data across multiple ERAs reveals denial patterns by payer, procedure, surgeon, or facility. For example, repeated CARC 4 denials on a specific payer may indicate a claim submission workflow failure, while repeated CARC 97 denials on a specific CPT pair may indicate a bundling rule the coding team has not accounted for.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's billing layer intersects with ERA processing at several points. When Mira selects or validates a modifier — for example, appending modifier 59 or an X-modifier to distinguish a separately identifiable orthopedic service — it does so in part to pre-empt the CARC 97 bundling denial that would otherwise appear on the ERA. If that denial still arrives, Mira can flag the CARC/RARC combination against the original code selection logic to determine whether the denial reflects a coding error, a payer policy deviation, or an editable claim issue. On the documentation side, Mira captures operative detail — implant type, approach, anatomical level, fracture character — that maps to the specificity required by ICD-10 seventh-character extensions and CPT add-on codes. Accurate upstream documentation reduces the frequency of ERA lines carrying CARC 5 (procedure is inconsistent with the place of service) or CARC 50 (non-covered service), both of which are common in orthopedic ambulatory surgery center claims. Mira does not auto-post ERA payments. Payment posting and accounts-receivable reconciliation remain with the billing team. However, Mira's denial-trend visibility can surface patterns — such as a specific payer consistently under-reimbursing total knee arthroplasty implant charges — so that the practice can address the root cause contractually rather than correcting claims one at a time.

See Mira's approach

Related terms

Clearinghouse Billing

A clearinghouse is a third-party intermediary that receives electronic claims from a provider's billing system, scrubs them for errors, converts them into the payer-required format (typically HIPAA 837), and forwards them to the appropriate insurance payer for adjudication.