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Insurance Claim REJECTED 2 - How To Appeal an Insurance Denial

How to avoid or Appeal an Insurance Denial


There is nothing that will incite fear and anger more than receiving a denial letter from your insurance company for a lifesaving treatment.  As if the journey battling autoimmune encephalitis wasn’t hard enough already…Wham…your insurance company has just slammed the door on your ability to get the treatment your expert neurologist has determined to be your path to the best outcome. Autoimmune Encephalitis is  a costly condition and we are here to help you navigate denial pitfalls. 

So, calm down. We have your back. This page will walk you through the necessary steps you will need to take to get your denial overturned. 

The appeals process is called the ‘Internal appeal’.

This is when the patient asks for a review of the decision that lead to the treatment being denied. Patients have a right to know why the treatment was denied and have a review of the decision.  If the denial of treatment puts the patient’s health in jeopardy, an expedited appeal is requested by the treating physician where a decision will be made in 10 working days.  An expedited appeal is routinely requested by the physician when a treatment for autoimmune encephalitis has been denied and is the recommended course of action to take to ensure success in your appeal. In the internal appeal, there are two appeals, First Level and Second level. If both are lost, you will be directed to an IRO or Independent Review Organization for an unbiased review. 


Under the law, Federal  statute 45 CFR 147.136 all appeals must be to a licensed Insurance company. We have received recent reports that some patients are being directed to appeal to their pharmacy or another group.  While an Insurance company may want to send your appeal to groups who may determine your appeal, it is your responsibility as an educated consumer to follow the federal statute and only send the first step, and second step appeals to your licensed insurance carrier.

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A second appeal option is to request an independent third party to review the decision. This option is one we strongly recommend you do not jump to.  All decisions are final, Therefore, you run the risk of all the proper research, chart notes, and evidence accrued in your case not being included in the submission weakening your position.  Jumping to this option, in the misguided opinion that it will hurry things along, is a self-inflicted wound you will not be able to reverse.  

 The independent review organization (IRO) must not be connected to either the patient or the insurance company and must provide a review from a physician that specializes in the areas of medicine the claim is related to such as a Neurologist or Neuroimmunologist.  This may not be a physician who has expertise in Autoimmune Encephalitis and may very possibly be a physician who has never seen a patient with Autoimmune Encephalitis or is not current with the latest research in the field.  If the independent reviewer overturns the denial, the insurance company must approve the claim.  If the independent reviewer denies the claim, all decisions are final, and you have no recourse. 

Let’s put this in perspective:

Insurance companies are for profit businesses. 50% or less of patients who receive a denial, never appeal the decision. Insurance companies frequently automatically deny treatment requests as ‘experimental’ or ‘not medically necessary’ as a matter of business when dealing with expensive treatments. The 50% of patients who do appeal, 25% are denied again and don’t move forward in the appeals process assuming the effort will not be rewarded by an overturned denial. Some patients make the mistake of requesting an independent review organization (IRO) right away, losing the opportunity to present additional evidence that will win their appeal, or failing to identify an error that was made in the prior authorization that caused the denial. So, you see, the financial gain for the insurance company is exponential. 

​When we get a denial letter stating the treatment is ‘experimental’ or ‘investigational’, some patients take that at face value. Thinking there is no other course of action, patients and families make the mistake of paying out of pocket or conducting fundraisers to afford the treatment that will save our lives. We see evidence of this with the overwhelming amount of “Go Fund Me” campaigns for medical treatments.

 For those who choose private pay, the facility who administers the treatment is often not billing you at the same discounted rate they would bill the insurance companies they contract with for the same service. Too often when we assist someone in their appeal, we uncover that they were billed at a higher rate; many times, 5 times more. Under USA tax law requirements for 501(c)(3) Hospitals Under the Affordable Care Act – Section 501(r), this could be what is considered gouging for a nonprofit hospital.  Billing should be equal to the arranged discounted rate the facility gives to large insurance companies knowing that they will have repeat business. 

 Making the mistake of paying out of pocket sets a precedent.  The patient will need multiple treatments for several years. By making this error, under the duress and concern that your loved one receive treatment as soon as possible, you have now set the stage that you will be paying out of pocket moving forward. This has caused families to go bankrupt and lose their homes. Our goal is to ensure that this never happens to you. Because you will become the master of what we call “The Denial Game”.


To reach ‘Check Mate’ in a game of chess you need to anticipate your opponent’s next moves and strategy.  Fear not.  We know their classic moves and have assisted in overturning 1,000s appeals for members of the autoimmune encephalitis community over the last decade. At some point in the appeals process, whether that be at the beginning addressing your first denial letter or at the end of the process in an IRO, your chances are exceedingly high that you will get your denied treatment overturned by following this advice.



Most treatments for antibody-mediated Autoimmune Encephalitis are not FDA-approved. They are ‘off-label’ treatments. More than one in five prescriptions written in the U.S. are for off-label treatments. Off-label use is so common, that virtually every drug is used off-label in some circumstance. 

An FDA-approved label is a written report that provides detailed instructions regarding the approved uses and doses, which are based on the results of clinical studies that the drug maker submitted to the FDA.  Clinical studies cost the drug manufacturer a great deal of time and money.  Since ‘off label’ use is so common, for example: a medication for high blood pressure that has been proven to carry a side effect for headache relief is prescribed to a migraine patient. This allows the drug manufacturer to increase sales with a proven safe and effective medication without investing assets in conducting a clinical trial for its use for headache relief. There is no motivation for the drug company to spend money on additional clinical trials when they have all the customers they could possibly want.  This is why many drugs that successfully treat other conditions lack FDA approval for autoimmune encephalitis.

 In dealing with a treatment that is not approved by the FDA for the diagnosis, the insurance company can deny the prior authorization for the requested treatment for the reason: “Not approved by the FDA” and we have just been Check Mated.  Therefore, we always keep their ‘check mate’ move in mind before we make our first move in the game seeing prior authorizations approved when they are submitted.


The insurance company doesn’t play the ‘Denial Game’ by check mating their customer/patient when they first respond to the doctor’s prior authorization for treatment.  They don’t use heavy guns up front declaring: ‘Denied- not FDA approved’.  The insurance company’s first response, from our experience, takes several factors into consideration: 


  • Our policy states specific medical conditions we cover for this treatment. The diagnosis stated in the prior authorization is not on the list of conditions we cover for this treatment. Request denied.


  • The evaluations and tests conducted that caused the clinician to arrive at the diagnosis, are insufficient: Request additional test results/evidence the doctor needs to work up on their patient to show the diagnosis to be accurate and the treatment requested appropriate. Research to reinforce this is also submitted by the doctor for the appeal. If due date for receiving this additional information expires, the insurance company will deny the prior authorization. (this is a reasonable request by the insurance company).


  • Insurance company requires more information/documentation/chart notes of the patient’s response to prior treatments and how the patient is currently presenting. If due date for receiving this additional information expires, the insurance company will deny the prior authorization. (this is a reasonable request by the insurance company).


  • In reviewing treatments, the patient has received prior to the requested treatment in the prior authorization, if a less expensive treatment in the protocol for treating the diagnosis has not been provided, the insurance company will deny the prior authorization by requiring that the patient receive an alternative treatment in the treatment protocol before approving the requested treatment. In this situation, the physician will need to document why the patient would not be able to tolerate other treatments in the protocol and provide documentation/chart notes/test results and research to respond to the denial. The physician documents why the treatment requested is appropriate for that patient and includes peer-reviewed research to enforce their opinion. If this information is not provided, the treatment is denied.


  • The insurance company states that there is not enough peer-reviewed research to show that the treatment is safe and effective. The prior authorization is denied saying the treatment is ‘investigational’ or ‘experimental’. 



Your doctor is aware and anticipates the possibility of a denial and understands how to ‘play the game’. To prevent a denial, the doctor will submit the chart notes, test results that confirm patient’s current diagnosis, presentation and past response to treatments administered to date to make the case for medical necessity.  Furthermore, the doctor should submit research that backs up his/her treatment request as treatment that is safe and effective including dose and frequency.  (Unfortunately, doctor’s do not always submit this research.  As an advocate, you will ensure that this occurs). All these components act to overcome the insurance company’s argument for denial.

These are the predetermined moves the insurance company makes before receiving any prior authorization for treatment. Since most of the treatments are not FDA-approved for Autoimmune Encephalitis, we are frequently appealing treatment denials in our journey to possible remission and recovery.

‘Human Error’ ` The Wild Card That Can Throw Us Off Our Game​


You now know the insurance company’s strategy.  The Insurance company can pull the ‘Not FDA-approved’ card at any time. Throughout the insurance denial process, your goal is to prevent the insurance company from making that checkmate move. ​ 

You are not alone in playing this game.  The Doctor and their staff are also on your team.  These team members are ‘wild cards”. Your doctor realizes this is a lifesaving treatment and daily plays the game to win. Doctors who are not experts in the field of autoimmune encephalitis and/or have had few patients with this diagnosis, might submit prior authorizations without the strongest data for success.  Each time a doctor submits a prior authorization for a specific diagnosis, particularly a rare disease, they refine their skills a bit more in how to play ‘the denial game’.  Your doctor knows the insurance company’s strategy, but they may not have played this game as often with a rare disease.  Therefore, we must include the doctor as a ‘wild card’.  Your aim is to be a supportive team member and advocate on the team. 

​Doctors usually have a designated medical staff member in their office who handles all prior authorization paperwork for the practice. This could be a clerical staff person, the doctor’s RN, or Medical Assistant.  This designated person should be considered a ‘wild card’ in the denial game due to the possibility of human error.  Additionally, if the doctor’s chart notes are insufficient or their writing is illegible, human error can occur. It is imperative to recognize the vulnerabilities of ‘Team members’ so you can give them the support they need to win the Denial Game.



Mistakenly using the wrong diagnostic code is the most common reason a prior authorization is denied! Just as the right key opens the lock, the correct diagnostic code gets treatment approved!  In our experience working with members in the AE community, at least 95% of the time, a prior authorization is denied because the person in the office who is in charge of doing prior authorizations used the wrong diagnostic code. It is the easiest human error mistake to make and is often never caught. It is also one of the easiest mistakes to rectify resulting in getting treatment approved.

When the wrong diagnostic code is mistakenly used on a prior authorization and the treatment is denied, the appeal can move through the internal appeal process,  peer to peer reviews are conducted, 2nd appeal, and sent to an IRO where all decisions are final with NO ONE ever catching the fact that the WRONG diagnostic code was used to begin with.

A diagnostic code is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.  Doctors usually use more than one diagnostic code. The primary diagnostic code is the most important one.

The code for Autoimmune Encephalitis


Sometimes the patient has developed other issues as a result of their Autoimmune Encephalitis (primary condition G04.81). The physician may use additional codes to back the primary code up if the patient has other issues that apply to the treatment they are requesting.

Example: Karen has G04.81 – Limbic Encephalitis (in her case LGI1 antibody positive), but she has also developed polyneuropathy because of her autoimmune encephalitis.  The diagnostic code for Idiopathic progressive polyneuropathy is G60.3.  IVIG is an FDA approved treatment for G60.3.  Medicare approves IVIG for G60.3.  The doctor knows that Medicare is the litmus test for what are approved treatments. Using this approach, the doctor’s secondary diagnostic code will get treatment approval if the primary one for Autoimmune encephalitis does not. Secondary codes reinforce the strength of the primary code. Your doctor will never use and never should use a diagnostic code that is not appropriate for the patient.

The physician is aware of the game, but human error is always a high possibility as we begin to play the ‘Denial Game’. Therefore, verifying that this code is the primary code used on the prior authorization is the first move you make in advocating for treatment approval.  Don’t be surprised when your doctor tells you he was planning on using a different diagnostic code. He may not have done many prior authorizations for treatment of antibody mediated autoimmune encephalitis or he has left that office procedure in the capable hands of his staff. Although they do prior authorizations all day 5 days a week, they don’t often file them for a rare disease which increases the risk of error.  

If the person doing the prior authorization uses a more general code, such as for Encephalopathy, unspecified or Encephalitis and encephalomyelitis, unspecified (as there are several codes to choose from), the diagnostic code is not specific enough and there is a high likelihood of denial. Alternatively, the incorrect code could be used when the chart notes don’t have a matching code. In other words, the doctor is referring to a name of a condition that has not been classified, so no code exists! Here is an example so you can see a common mistake and understand how easily human error can occur.

The patient has ‘Hashimoto’s Encephalitis’. This is what autoimmune encephalitis was frequently called for many years when the patient did not have an identified antibody and was positive for out of range thyroid antibodies and presented with symptoms of AE. This is known as Autoimmune Encephalitis today but the name ‘Hashimoto’s encephalitis’ is still used by some neurologists today who have been in practice for many years and have not ‘updated’ to the name change. The person who does the prior authorizations sees ‘Hashimoto’s Encephalitis’ and searches through the diagnostic codes that match it. There is NO diagnostic code for Hashimoto’s encephalitis but there is a diagnostic code for Hashimoto’s Thyroiditis. So, for whatever reason, it could be the chart notes say ‘Hashimoto’s’ or the patient also has a diagnosis of Hashimoto’s thyroiditis, the person puts down the code: E06.3 and submits the prior authorization for a treatment that is not used to treat Hashimoto’s thyroiditis. The treatment requested doesn’t match the disease. It is denied as not medically necessary due to ‘investigational’ or ‘experimental’.

This mistake is the most frequent example we see in human error working as patient advocates helping patients get their denials overturned. Alarm bells sound when we hear a patient with a diagnosis of Hashimoto’s Encephalitis ask for help in appealing their treatment denial. This problem is then compounded when the doctor is informed that the prior authorization for treatment was denied and doesn’t notice that an incorrect diagnostic code was used. Doctors depend on their staff to back up the running of their office and may not review the denial personally or catch the error.


If you have read this page before your doctor has put in a prior authorization for treatment and are reading to educate yourself as you have heard that treatments are frequently denied, you now know what needs to be submitted for a successful prior authorization.


1.The doctor includes all tests, lab results, evaluations that lead to the diagnosis, the treatments they have given to date and patient’s response and makes the case for medical necessity.
2.The diagnostic code for antibody mediated Autoimmune encephalitis used is G04.81
3.Research showing the treatment is safe and effective that includes dose and frequency in the research is printed out. (including tables and figures) and faxed with the prior authorization.


The letter will state the reason for denial, what the diagnostic code was, and usually what diagnostic conditions the insurance company covers for that treatment. If the letter does not include what medical conditions it covers for the treatment, look this information up in your policy.

Step 1: look up the code if it is not G04.81.

Is the treatment that was requested a treatment proven to be safe and effective for treating the disorders under that code? Is the code for Hashimoto’s thyroiditis when it should be for Autoimmune Encephalitis? Is the code too general and not specific enough?

Often the denial letter will list what medical conditions the policy covers for the treatment. Does the patient have one of those conditions as well? Take a careful look at what the insurance company covers. There are many syndromes in autoimmune encephalitis (see charts that include syndromes on antibodies) and some of these are listed in many policies individually. So, although autoimmune encephalitis may not be listed, the clerical worker at the insurance company, the patient or caregiver helping the patient, might not be aware that some of the approved diagnosis for the treatment being requested are indeed syndromes in autoimmune encephalitis that are listed in your policy. Therefore, the insurance company is saying that they are denying your treatment because they do not cover autoimmune encephalitis when they are listing syndromes seen in autoimmune encephalitis. Some of these that are frequently listed in policies are: Stiff-Person Syndrome and Lambert-Eaton Myasthenic Syndrome (LEMS). Both are identified through positive antibody testing in antibodies in Autoimmune Encephalitis

The argument becomes:

Why does my insurance company say that my treatment is denied because autoimmune encephalitis is ‘investigational’ or ‘experimental’ when they approve treatment for autoimmune encephalitis syndromes? They don’t cover some forms of AE but do cover other forms of AE? Be aware that the policy writer was not aware that these were syndromes under autoimmune encephalitis. Research that discusses treating autoimmune encephalitis that references LEMS or Stiff-person (SPS) in the body of the research paper, would then be submitted with the appeal. And a notation of this would be mentioned in the appeal letter.


Kathie received a denial letter for Rituxan for her Autoimmune Encephalitis. Kathie also has rheumatoid arthritis. Rituxan is FDA approved for rheumatoid arthritis. Kathie asked her doctor to put in a NEW prior authorization with the insurance company for Rituxan to treat her rheumatoid arthritis. (An appeal is not done if you are dealing with the wrong code. A new prior authorization is submitted.) Kathie’s insurance company approved her Rituxan treatment.


Ava needed IVIG to treat her Autoimmune Encephalitis. Ava also has a Common variable immunodeficiency (CVID) code D83 another common code that is used but frequently denied is D89.89. Compare these two diagnostic codes. Do you see that D83 is a much stronger code to use than D89.89? Can you see why diagnostic code D89.89 would have a high frequency of being denied because it is so general and vague? The doctor’s office submitted a prior authorization for IVIG using the CVID code D83 as the FDA approves the treatment of IVIG for CVID.


The patient has Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) in addition to Autoimmune Encephalitis. The insurance company has denied IVIG for autoimmune encephalitis. The diagnostic code for CIDP was not used in the prior authorization. In this case, the denial is not appealed. A new prior authorization is written using the diagnostic code G61.81 for CIDP. IVIG treatment is an FDA approved treatment for G61.81 so the prior authorization with be approved.

Action Step:

I have a diagnosis that is FDA approved for this treatment other than Autoimmune Encephalitis. I have a medical condition that is listed in my insurance policy as covered for this treatment:


FDA Approved Uses for Intravenous Immunoglobulin

FDA Approved Uses for Rituxan/Rituximab


If you have a diagnosis other than autoimmune encephalitis that is covered for the required treatment. Call the doctor’s office and ask to speak with the staff member who submits prior authorizations. The doctor’s office would have been notified by the insurance company of the denial prior to your denial letter arriving.  Inform the staff person in charge of prior authorizations that you received your denial letter and you also have a diagnosis that is covered for this treatment.  Ask them to submit a NEW prior authorization for the diagnosis you have that is covered for the treatment and ask them to expedite the processing of the NEW prior authorization. The staff person can fax the new prior authorization and call the insurance company to see that it is received and ‘walk it through’ to approval on the same day.  Back this telephone call up by contacting your doctor in the patient portal and letting them know of the request you made of the staff person in putting in a new prior authorization. Ask the doctor if they or their staff person will get back to you that same day with an update. Doctor’s offices are busy places and the staff member will need to catch the doctor in between patients to accomplish submitting the new prior authorization request. By informing the doctor of the solution, they will keep an eye out for the staff person during the day to make sure this is accomplished.




One of the first things to check when you receive a denial letter is to verify what diagnostic code was used. If you suspect that an incorrect diagnostic code was used, call the doctor’s office and ask to speak with the staff member who submits prior authorizations. The doctor’s office would have been notified by the insurance company of the denial prior to your denial letter arriving.  Inform the staff person in charge of prior authorizations that you received your denial letter and you noticed that the incorrect diagnostic code was used.  If you have a diagnosis of Autoimmune Encephalitis as defined on this website and you have checked the list of disorders/disease processes that are included under that code and it matches the diagnosis your doctor has given you, diagnostic code G04.81 as mentioned above, instruct the staff person to STOP any action moving forward to appeal the denial and have them submit a NEW prior authorization with the correct code: G04.81. Additionally, tell the person in charge of prior authorizations in your doctor’s office that you want them to submit peer reviewed research scientifically proving the treatment is safe and effective.  This research will need to be printed out along with any tables and figures included within the research paper. (See links below).  The research should be sent with the new prior authorization. Please note that the most important research papers to send to prove the treatment is safe and effective are those that include the details of dose and frequency.


Download Studies to Show IVIG is Safe and Effective for Autoimmune Encephalitis – Diagnostic Code G04.81

​Download Studies to Show Rituxan is Safe and Effective for Autoimmune Encephalitis – Diagnostic Code G04.81

Download Studies to Show Tocilizumab is Safe and Effective for Autoimmune Encephalitis – Diagnostic code G04.81

Download Studies to Show Plasmapharesis is Safe and Effective for Autoimmune Encephalitis – Diagnostic code G04.81

Download Studies to Show Mycophenolate Mofetil (cellcept) and Azathioprine (Imuran) is Safe and Effective for Autoimmune Encephalitis – Diagnostic code G04.81

 Since there will be members of the public reading this page who have a different diagnosis other than antibody mediated AE such as ADEM or a post infectious diagnosis of Encephalitis and encephalomyelitis, unspecified – diagnostic code, G04.90, we have included a link to research to be printed out and included in either a new prior authorization or a prior authorization that is being submitted for the first time. (See link below for G04.90 if the treatment is for IVIG).  

Download Studies to Show IVIG is Safe and Effective for Encephalitis and Encephalomyelitis, ADEM Diagnostic Code G04.90 



Pre-approval is not needed with traditional Medicare. The doctor prescribes a treatment, and a claim is sent to medicare. If medicare denies the claim, the patient is held harmless under the law and cannot be billed. If the hospital seeks to be paid, it is their obligation to provide the necessary paperwork that supports the use of the treatment that was provided to the patient. 


IMPORTANT TO NOTE: If the traditional Medicare patient, (that is the red, white and blue card), signs a contract called an Advance Beneficiary Notice, with the hospital or doctor stating that they agree to pay the hospital or doctor in the event medicare does not, then the patient either has to pay any additional amount billed or appeal the denial.
We recommend that in order to protect yourself from high out of pocket costs, that you not sign the advance beneficiary notice. Patients are not obligated to sign an advance beneficiary notice because medicare will pay. This is a protection that traditional medicare offers. If you do not sign the contract saying you will pay if medicare does not, you will be under no added financial obligation and the physician or hospital will receive its payment in full as per Medicare’s coverage. Should the need arise and you are faced with filing a complaint, review this article:

How to File a Complaint Against Your Medicare Drug or Health Plan 

​Other helpful articles are:

 ​How to Appeal an Insurance Company Decision

 A Patient’s Guide to Navigating the Insurance Appeals Process

Starting the Appeal Process

How to Write an Effective Appeal Letter ​



Every year, more than 185,000 clinical trials are in progress worldwide, 40 percent of which take place in the United States, according to the National Institutes of Health (NIH). And one of the biggest challenges for researchers is attracting enough volunteers. For someone with a life-altering disease, participating in a clinical trial may offer hope for a better treatment OR access to treatments your insurance company has denied you. Keep informed about clinical trials that may be helpful to you and discuss this option with your Physician. This primer will keep you connected with clinical trials and how to volunteer.


extinguish NMDAR encephalitis trial

If you have a recent confirmed diagnosis of anti-NMDAR encephalitis and are 18 years + you may qualify for the first-ever Clinical Trial treating anti-NMDA receptor encephalitis. Learn more. 

E-mail IAES with your success stories and pictures of patient receiving treatment that was previously denied. (By submitting your pictures you give permission for use in future instructional or awareness videos). If this page helped you over turn your denial and win your appeal, please consider making a donation to support our outreach.
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Our website is not a substitute for independent professional medical advice. Nothing contained on our website is intended to be used as medical advice. No content is intended to be used to diagnose, treat, cure or prevent any disease, nor should it be used for therapeutic purposes or as a substitute for your own health professional's advice. Although THE INTERNATIONAL AUTOIMMUNE ENCEPHALITIS SOCIETY  provides a great deal of information about AUTOIMMUNE ENCEPHALITIS, all content is provided for informational purposes only. The International Autoimmune Encephalitis Society  cannot provide medical advice.

International Autoimmune Encephalitis Society is a charitable non-profit 501(c)(3) organization founded in 2016 by Tabitha Andrews Orth, Gene Desotell and Anji Hogan-Fesler. Tax ID# 81-3752344. Donations raised directly supports research, patients, families and caregivers impacted by autoimmune encephalitis and to educating healthcare communities around the world. Financial statement will be made available upon request.

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