What is an Explanation of Benefits (EOB)?

An EOB, or a Remittance Advice, is the documentation from your insurance company showing how they processed your claim. It should show the amount billed by your provider, the amount paid to your provider per the contract, any reasons for not paying or for denying part of the claim, and the amount that you owe. The EOB is an important document to have available if you need to discuss your bill with your provider or your insurer. There is no standard format for EOBs, but they all have generally the same elements.

What is a denial from an insurance?

Sometimes your insurer processes your claim and determines that they are not going to pay part or all of it. This is known as an insurance denial or rejection. When your service is denied, you will usually receive an EOB with a code or description explaining why it was denied. In many cases, an insurance denial may become your responsibility to pay.

Why would my insurance deny service?

Services are denied for many reasons, usually accurately but sometimes inaccurately. Common reasons why your claim may be denied include duplicate bills (the insurer was billed twice for the same service), the service was not covered by your plan, or the treatment was miscoded by your provider. These are just a few of the reasons – there could be dozens, but it should be clearly communicated on the EOB.

How long should it take for the claim with my insurance to be resolved?

It depends on several factors, but most claims which have no major issues are resolved within 45 days.

What should I do about a denied service?

How you respond to an insurance denial for your service depends heavily on the type of denial.

What is a network, as in in-and-out of network?

Most insurance plans include a network of providers, or a group of preferred doctors and medical practices for their members (you, if you are insured by them) to see. When you seek your care through one of those providers, are you “in-network”. When you go to someone outside of that group for care, you are “out-of-network”. In most plans, seeking care outside your network means that you’ll pay a higher out-of-pocket amount.

What is an authorization?

Some insurances require that you get an authorization from our insurance prior to receiving medical care. This is typically done by calling the number on your insurance card, explaining what procedure or service you require, and often involving your provider to supply additional information. You typically will receive an authorization number or letter indicating that your insurance approves the service. While not all services require a prior authorization, the best approach is to contact your insurance any time you think an authorization may be required or are not sure. Pre-certification, or Pre-certs, are the same as prior authorizations.

What hasn’t my insurance paid for my care yet?

Insurances can take 30, 45, or 60 days or more to process a claim. While most simple claims are processed quickly, more complex claims may take longer. Your insurance may ask you or your provider for additional information such as portions of the medical record or documentation of service. Until all requests have been filled and reviewed, your insurance will likely not pay for the care.

Calling the member services number on your insurance card can usually enable you to understand where in the process your claim currently resides.

What is the difference between an HMO, and PPO, and a POS plan?

HMOs, PPOs, and POS plans are three examples of products offered by insurance companies, and there are several hybrids of these as well as additional types of plans. You can see our complete guide here.

Why is my bill being discounted for my insurance company?

Many providers have agreements with insurers to accept certain terms and payments when their members are treated. If you see a “provider discount” or “contractual allowance” on your EOB, it means that the total charges from your provider were adjusted down based on one of these agreements.

Does my doctor have to accept my insurance?

Most providers accept most insurances, although not all insurance may be in their network. However, in some cases such as Medicaid, providers can’t recover the cost of treating you from the payer. Providers may limit the number of patients from such payers given the financial constraints.

I received a letter from my insurance asking for additional information. What should I do?

If your insurer requested additional information, such as a medical history or summary of other insurances you carry, they are likely pending payment on your claim until they receive the documentation. If you need assistance gathering medical or clinical information, call your provider’s billing office. They may be able to assist you.

I have more than one insurance. How does that work for claims payment?

Provide the names and policy numbers of each insurance plan to your provider’s billing office. Be sure to let your provider’s office know which insurance is primary, and which is secondary. In some cases, one plan may be for preventative care, and another may be for medical services, so be sure to specify that so your provider has it in their system. Your provider should be able to bill according to the correct order but be sure to keep your EOBs from the insurance companies, as these can be complicated cases where the documentation will prove useful.


  1. A supplement is great, but they can deny you coverage if you have too much health-related issues. Also, they go up, up every year and can be too much for a lot of people.

  2. I am not yet retired and have had an HMO for the majority of my work life. Never had to use it much until this past year when I suddenly had three major health issues that are overlapping, and need addressed one at a time. My HMO has been stellar thus far–better than I could have dreamed of, actually. There was one minor network snafu that was resolved after I called my insurer. (They agreed to pay full allowance to an out-of-network specialist when there wasn’t one in my network.) I dread having to go on Medicare when I retire. I have been telling my “better off” friends to go with original Medicare and supplement. I know what you’re saying and can’t disagree, but I’m a single person with a home to maintain. My retirement income isn’t going to be very good but I’m hoping to scrape by. I will price original Medicare and a supplement, but I really don’t think I’ll be able to afford it and keep a roof over my head at the same time. Even now, with a full paycheck, I live pretty frugally. I know not to consider zero-premium Advantage Plans. The best I can do is a lot of comparison shopping for one since I do know most of what to look for from varied life experience in medical field and medical insurance company. I’ll read and ask questions until I find one, I can hopefully live with. That said, I know that for the sake of profit the Advantage Plans (or at least some of them) deny payment for services that are considered medically necessary by original Medicare and so many people are just too tired or busy to fight it. And I don’t think, at this time, you can go to the feds to complain–only your Advantage Plan insurer. Did see a study came out recently where federal Medicare took note of what the Advantage Plan insurers are up to. So maybe (big maybe) the situation will improve.

  3. I am a retired RN on original Medicare and a supplement. I chose this over an Advantage plan based on my experience working in a cardiology clinic where we had to get pre-approval for various diagnostics and procedures from Advantage plans. It was sometimes a drawn-out procedure, resulting in delays or denials from these insurance companies who are not in a good position to make these determinations. One time, an agent from one Advantage plan sent a message to one of our cardiologists asking why he thought he should do a particular test. The exasperated cardiologist said to tell her “Because I am a cardiologist, and you are not.” I will say that it is also true that some doctors have stopped accepting original Medicare because their reimbursement is lower, not sure if that is regional or by specialty or what, and I don’t know how widespread that is. But those doctors may then have the added expense of a larger staff to deal with pre-approvals. All I know is there is no one between you and your doctor, slowing or stopping your care with original Medicare, and you have a network wherever you go.

  4. I’m the youngest in my family and having older siblings really helped me understand the difference between Advantage and original Medicare with a Supplemental plan. By the way, F has been phased out for new enrollees. I’ve got G and it runs $150. per month (note that the premium goes up every year as you age). Also, if you were to get Advantage initially and wanted to change to original Medicare/Supplemental, you may not qualify, as preexisting conditions are taken into account during the approval process for the Supplemental. The only time preexisting is not a factor, is when you already have health insurance and are applying for Medicare/Supplemental for the first time.

    Depending on your income, some people can’t afford original Medicare/Supplemental and have to go with Advantage. Lucky for me, the employer I retired from reimburses me monthly for my Medicare/Supplemental premiums, but even if they didn’t, I would still go with original Medicare/Supplemental. I retired in a rural area (it was originally my secondary home) and have heard many horror stories about the lack of coverage, denial for treatment, hidden costs and the scarcity of doctors who accept Advantage in rural areas.


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