What is a letter of medical necessity (LMN)?

a letter of medical necessity turns a sour situation sweet

If you’ve had a pre-tax account before, you may have heard of a certificate or letter of medical necessity. It is sometimes abbreviated as LMN (pronounced “lemon”).

Why do I need a LMN?

A LMN is used in circumstances when a person wants to use funds from their pre-tax account but the item or service is not universally recognized as an eligible expense by the IRS. This happens most often when an item or service is considered dual purpose. In other words, the primary purpose of the service isn’t medical but due to a medical condition, it provides medical benefits.

When a LMN is completed by your health care provider certifying that the service/product is medically necessary and submitted with a claim, this will allow for reimbursement of the service/products.(However, providing a LMN does not mean the expense will automatically be approved).

Sample dual-purpose services that would require a LMN:

  • OTC medicines
  • Alternative therapy (e.g. massage therapy)
  • Air conditioners / filter / purifier
  • Supplements
  • Allergy products and treatments
How do I get a LMN?

If your pre-tax benefits are administered through BRI, you can obtain a LMN (referred to as a certificate of medical necessity) easily by visiting the Forms section on

Download the form, have your doctor or health care provider fill it out, and submit it to BRI with your claim for reimbursement.

Do I always need to submit a LMN?

You do not need a LMN if you are purchasing a product that is universally eligible. If you want to know what’s eligible, you can start by looking online at the FSA Store. (You can also read more about what a LMN is in this article from the FSA Store).

Getting started

The crux of the matter is that if you want to use funds from a tax-free account, there are certain situations when you may need to prove that the medical service or items you are purchasing are eligible to be paid with funds from your plan. A letter of medical necessity is the path to help you achieve that.

In short… When life gives you LMNs, make lemonade.