Auto-Adjudication of Claims and ERAs: What Automation Saves

Ideally, no one has to work a claim by hand. The charge arrives from the treatment or clinical system, passes the scrubber, goes out as an 837, is adjudicated by the payer’s system without a person reading it, and comes back as an 835 that posts automatically while the payment arrives by EFT. Auto-adjudication is the payer’s term for the middle step, a claim decided entirely by rules, and billers now use it for the whole process. This post began as three drafts in 2014, when much of that process was not yet automated. The useful questions in 2026 are where staff still have to step in, and what a fully automated claim saves.

If your office still prints remittances to post them, this post explains what automation can save.

The process, transaction by transaction

Step	What moves	Standard
Charge import	Demographics, insurance and CPT charges from the EHR or the record and verify system into billing	HL7 or a direct integration
Scrub	Edits against coding and payer rules before the claim is built	Practice or vendor rules
Claim out	The professional claim to the clearinghouse and payer	X12 837, Health Care Claim: Professional (005010X222)
Acknowledgments	Accepted or rejected at the clearinghouse and payer front end	X12 999 and 277CA
Eligibility and status	Coverage check before service; claim status while waiting	X12 270/271 and 276/277
Adjudication	The payer’s system prices and decides the claim	Payer internal
Remittance	Payment and adjustment detail per line, with CARC and RARC codes	X12 835, Health Care Claim Payment/Advice (005010X221)
Payment	Funds to the bank, matched to the 835 by trace number	EFT
Posting	The 835 applied to patient accounts without a person keying it	Billing system auto-post

Medicare has used these transactions for years. All electronic remittances from Medicare contractors are in the X12 835 version 5010 format, and CMS notes that payment and adjustment data “can be automatically posted to accounting or billing applications from an ERA.” The 2014 drafts described charges importing from Aria or Mosaiq and the ERA posting “without manual intervention by provider staff.” That is now standard.

What it saves

Days. Medicare’s payment floor is the earliest day a clean claim can be paid: the 14th day after receipt for a HIPAA-compliant electronic claim, the 29th day for paper. An electronic claim can be paid 15 days sooner, every time, not counting mail time.

Medicare requires it. The Administrative Simplification Compliance Act requires initial Medicare claims to be submitted electronically unless the practice qualifies for a waiver or exception, such as having fewer than 10 full-time equivalent employees. Paper Medicare claims are not an option for most practices.

Staff time. The 2014 drafts quoted an AMA estimate that paper claims cost roughly 50 percent more to process than electronic ones. The current industry measure is the CAQH Index. Its 2025 edition, released February 19, 2026, estimated that electronic transactions and better data exchange avoided 258 billion dollars in administrative cost in 2024, with a remaining 21 billion dollar opportunity from automating what is still manual or partly manual. Adoption of electronic claim payment on the medical side reached 78 percent and claim status 81 percent; electronic prior authorization, the lowest, reached 40 percent. The manual work that remains is concentrated in a few transactions, and prior authorization is the biggest.

Fewer posting errors. A paper EOB has a different layout for every payer, and reading PR-1 against CO-45 on a 40-line radiation remittance by hand is where posting mistakes come from. The 835 carries the same adjustment codes in the same fields from every payer, which is what makes a posting rule possible.

Where staff still have to step in

A claim with no manual work is the goal, but many claims still need a person. These are the places staff still have to step in. A good process sends them to a work list instead of leaving them mixed in with the auto-posted payments.

Front-end rejections. A 999 or 277CA rejection means the payer never adjudicated the claim. These are not denials and they do not appear on an 835; if nobody reads the acknowledgments, the claim stays unpaid and gets closer to the filing limit.
Denials from payer auto-adjudication. CO-16 (information missing, read the RARC), CO-197 (no authorization), CO-18 (duplicate) and CO-29 (timely filing) are decided by the payer’s rules in seconds. They come back on the 835 and should be excluded from auto-posting into “paid” status and added to the denial list.
Zero-pay and takeback lines. A line paid at 0.00, a reversal and corrected claim pair, or a provider-level adjustment (the PLB segment) for a recoupment or interest needs review by a person before it is applied.
Secondary claims. The primary 835 should create the secondary claim automatically, with the primary payment and adjustments carried in the 837’s coordination of benefits loops. When it does not, the secondary is built by hand and is often late.

Worked example: one 835, forty lines

An illustrative Medicare remittance for a freestanding radiation center covers eight patients and 40 service lines, mostly 77407, 77387-26 and 77427, plus two 96413 infusion lines.

36 lines paid as expected: billed amount, CO-45 contractual adjustment to the allowed amount, PR-1 or PR-2 for the patient share, payment. The posting rule applies all 36 and marks the patient portions for statements. No one reads them.
2 lines of 77427 denied CO-16 with remark N4 (missing or incomplete documentation). The rule recognizes CO-16, posts nothing, and routes both to the denial queue with the claim and remark attached.
1 line of 96413 paid at 0.00 with CO-18, duplicate. Routed for review; it turns out to be a corrected claim sent before the original was processed.
1 PLB entry recouping 412.00 from a prior remittance. Held for a person to match to the earlier claim before it is applied.

Thirty-six of forty lines posted with no manual work. The other four were in a work queue the same morning, instead of in a paper stack waiting for someone to get to it. Automation does not handle the hard cases, but it gives staff time to work them.

Setting it up

Enroll for 835 and EFT with every payer that offers them, and match the two by trace number so an 835 with no money, or money with no 835, is easy to spot.
Write posting rules by adjustment group and code: contractual (CO-45) posts, patient responsibility (PR) posts, everything else holds for review.
Read the 999 and 277CA acknowledgments daily and treat a rejection as an unsubmitted claim.
Keep the charge import complete. Automation cannot bill a charge that was never imported. That is a charge capture problem, covered in its own post.
Iridium Suite’s EMR and EHR integration connects the clinical and treatment systems to billing so charges and demographics arrive without re-keying, and its claim scrubber checks codes against billing and payer rules before charges post. That is the first step toward a claim with no manual work.

Claims automation: what auto-adjudication of 837 claims and 835 remittances actually saves