How to read an explanation of benefits (EOB), line by line

What an EOB is, and what it is not

An explanation of benefits (EOB) is the statement your health insurer sends after it processes a claim. It shows what your provider charged, what the plan allowed, what the plan paid and what you may still owe. The Centers for Medicare & Medicaid Services (CMS) puts it plainly: an EOB is not a bill.

The bill comes separately, from the doctor, lab or hospital. The EOB is your check on that bill. When the two don't line up, the EOB is usually where you start asking questions.

You may get one EOB per visit, per provider or per day of treatment. One hospital stay can produce several, because the hospital, the surgeon, the anesthesiologist and the lab often bill separately. Keep every EOB until the matching bill is settled.

The parts of an EOB, top to bottom

Insurers design their own layouts, but CMS describes the same core fields on most EOBs.

Who and when

• Patient. The person who got care. On a family plan, check this first; a claim filed under the wrong family member is a common mix-up.

• Health plan and member ID. Your insurer and your ID number.

• Provider. Who billed for the care. If the name looks unfamiliar, it may be a group practice or a lab that worked behind the scenes.

• Claim number. The reference you'll quote in every call or letter.

• Date of service. When you got the care.

What was done

• Service description. A short label such as "office visit," "lab" or "radiology." Some EOBs also show a procedure code, a five-character code that identifies the exact service.

The money columns

This is where most confusion starts. Read the columns from left to right.

1. Provider charges (amount billed). The provider's full price. Few insured patients pay this amount.

2. Allowed amount. The most the plan will pay for that service, often a rate negotiated with in-network providers. CMS notes it can differ from the provider's charge.

3. Discount or adjustment. The gap between the charge and the allowed amount. If the provider is in network, this is usually written off.

4. Paid by plan. What the insurer actually paid the provider.

5. Your share. What is left for you, split into deductible, copay and coinsurance. CMS calls the total "What you owe" or "Patient balance."

Remark or reason codes

Short codes next to a line explain why a charge was reduced or denied. CMS describes them as two- or three-character codes, with their meaning printed at the bottom of the EOB. Read every remark on lines where the plan paid less than you expected.

A sample EOB line, decoded

Here is a synthetic example from a fictional insurer, Northgate Health Plan.

Sample EOB · Northgate Health Plan (synthetic)

Date of service 04/02 · Northgate Family Clinic · Office visit, established patient

Amount billed $240.00 · Allowed $135.00 · Plan paid $0.00

Applied to deductible $135.00 · Patient responsibility $135.00 · Remark PR-1

How to read it: the clinic charged $240, but the plan's allowed amount is $135. The plan paid nothing because the $135 went toward your deductible, the amount you pay each year before the plan starts paying. The remark "PR-1" uses a standard code set in which "PR" means patient responsibility and "1" means deductible. If the clinic is in network, you should be billed $135, not $240.

Five checks to do with every EOB

1. Is this care you actually received? Match the date, provider and service with your own records or calendar. An EOB for care you never had is worth a call to your insurer.

2. Was the provider treated as in network? Many EOBs flag in-network and out-of-network lines. If you saw an in-network doctor and the EOB says otherwise, ask why.

3. Did the deductible and out-of-pocket totals move correctly? Many EOBs show year-to-date amounts. If you think you already met your deductible, compare these figures with your plan documents.

4. Was anything denied? A line with $0 paid and a reason code may be a denial, not a deductible. Look for words such as "not covered," "not medically necessary" or "authorization."

5. Does the provider's bill match? CMS says the bill should not be higher than the patient balance on the EOB. Remember that the EOB doesn't show payments you already made, such as a copay at the front desk, so subtract those yourself.

When the EOB raises questions

Call the insurer when

• a service was denied or partly denied;

• the provider is listed as out of network when you believe it is in network;

• the deductible or coinsurance doesn't match your plan;

• you don't recognize the provider or the date of service.

Call the provider's billing office when

• the bill is higher than the EOB's patient balance;

• you were billed before the insurer processed the claim;

• a payment you made isn't shown.

For each call, write down the date, the name of the person you spoke to and any reference number. CMS recommends keeping these notes in case you need them later.

If you need to appeal

If the EOB shows a denial, the insurer must tell you why and how to appeal. Under the rules described on HealthCare.gov, you generally have 180 days from the denial notice to file an internal appeal. Some plans may follow different rules, so check the deadline on your own notice. Keep a copy of the EOB with your appeal; it is the record of what the plan decided.

Questions worth asking the insurer

• "Which part of this claim was applied to my deductible, and how much of my deductible is left?"

• "What does remark code [code] mean on this claim?"

• "Was this provider processed as in network? If not, why?"

• "Is this a final decision, and what is the deadline to appeal?"

Get a second pair of eyes on your EOB

When EasyToDecode opens, you'll be able to upload an EOB or the matching bill and get every line explained in plain English, each quoted from the page. It will pull out the amounts and deadlines, flag lines that don't match, and draft questions you can send to your insurer or provider. See how it works or join the waitlist to hear when it opens.