EOB, ERA and EFT: what dental offices receive from insurers, and how they fit together

PearlFlow guides · November 12, 2026

If you post insurance payments, three acronyms run your week: EOB, ERA and EFT. They are related but not the same, and they often reach your office at different times and by different routes.

The EOB: the insurer's explanation

An EOB (explanation of benefits) is the insurer's statement of how it handled a claim after processing it. For each procedure, it typically shows the plan's allowance, the percentage the plan covers, any deductible applied, the amount the plan paid, and what the patient owes your office. Remark codes at the bottom explain reductions and denials (ADA).

Patients get an EOB too. The ADA defines it as a written statement to the plan member after a claim is processed, showing what the plan did and did not cover. So a patient may call about the same claim you are posting, with their own EOB in hand.

The ERA: the same explanation, in a standard electronic format

An ERA (electronic remittance advice) is the electronic version of that explanation. Under HIPAA, the required format is the X12 835, usually just called "the 835" (CMS).

The ERA explains the payment, including any adjustments for things like contract terms, secondary insurance, the patient's benefits, and expected copays and coinsurance. Adjustments are explained with standard codes (Claim Adjustment Reason Codes and Remittance Advice Remark Codes), and health plans may not use their own private codes in an ERA. Our guide to reading the codes on a dental EOB explains them.

Each ERA also carries a reassociation trace number, often called the TRN. Each 835 describes exactly one payment: one check or one electronic transfer.

The EFT: the money itself

An EFT (electronic funds transfer) is the deposit. The HIPAA standard sends it through the ACH (Automated Clearing House) Network, the same system that handles payroll direct deposit. A health plan can use your bank information only to deposit money, not to withdraw it.

The standard EFT format is called CCD+. Its "plus" is an extra record that carries the same trace number found in the matching ERA.

Why they arrive separately

A paper check and its paper remittance arrive in one envelope. An EFT and its ERA do not. The money travels from the plan's bank to yours, while the ERA travels from the plan to you, directly or through a clearinghouse.

Matching each deposit to its ERA is called reassociation, and federal guidance describes it as necessary for posting payments (CMS). The trace number is the link.

Two details trip up many offices:

The timing rule

Operating rules written by CAQH CORE, an industry rules body, have been required under HIPAA since January 1, 2014, and they set the timing. A health plan must send the ERA no sooner than three business days before the EFT's effective date and no later than three business days after it, and must meet that window at least 90% of the time each month (CAQH CORE).

If one piece is still missing four business days after the other arrives, it counts as "late or missing." Every health plan must have a written procedure for resolving this.

Paper checks, EFT and virtual cards

EFT spares you opening mail and depositing checks, but dentistry has been slow to switch. Nacha, which writes the operating rules for the ACH Network, reported in 2026 that dental EFT adoption was 33%, compared with 78% in medicine, citing the CAQH Index (Nacha).

Some insurers pay with virtual credit cards: a one-time card number you key into your card terminal. In a guidance letter dated March 22, 2022, CMS (the Centers for Medicare & Medicaid Services) said plans may pay this way. But if you ask a plan to pay you by standard EFT and ERA, the plan must comply, whether or not you are in its network, and that obligation extends to vendors paying on its behalf.

ADA News reported that a virtual card payment typically costs a merchant fee of 2–3% plus 10 cents per transaction (ADA News). HHS does not regulate those fees. If a plan does not honor your EFT request, CMS says you may file a complaint through its online enforcement tool, ASETT.

Why offices still download EOB PDFs

To receive EFT and ERA, you must enroll with each health plan you bill. Enrolling with one payer does nothing for the others.

So for any payer where your office has not completed ERA enrollment, no 835 arrives from that payer. The explanation of payment has to come some other way: a paper remittance mailed with a check, or an EOB from that payer's provider website. The CAQH Index also reports that dental staff download portal EOBs because electronic remittances often lack detail, and that using both portals and ERAs can lead to the same payment being posted twice (CAQH Index 2024).

A practical takeaway

  1. Enroll in both EFT and ERA with each payer. List every payer you bill and check off both.
  2. Ask your bank to send you the trace number for each insurance deposit.
  3. Match before you post. For each deposit, find the remittance with the same trace number and confirm the amounts agree. Only then post it to patient accounts. Our step-by-step posting checklist picks up from there.
  4. Chase the gaps. If a deposit or remittance is still missing four business days after its partner arrives, use that payer's late-or-missing procedure.
  5. Say no to virtual cards if you prefer. Ask the plan to pay you by standard EFT with an ERA. Putting the request in writing gives you a record.

Once every deposit has a matching remittance, and every payer is set up for both, posting gets much easier to trust.

Sources

This guide is general information, not legal or billing advice. Check your payer contracts and your state’s rules for your own practice.