Can you use HSA or FSA money for a blood test?

What the IRS counts as medical care

HSAs and health FSAs pay for medical care as the tax code defines it. IRS Publication 502 says medical expenses are the costs of diagnosis, cure, mitigation, treatment or prevention of disease, and for the purpose of affecting any part or function of the body. They must be primarily to alleviate or prevent a physical or mental disability or illness. Expenses that are merely beneficial to general health, such as vitamins or a vacation, do not count.

IRS Publication 969 ties both accounts to that definition, with one difference. For an HSA, qualified medical expenses are amounts paid for medical care as defined in section 213(d) of the tax code. For a health FSA, qualified medical expenses are those specified in the plan that would generally qualify for the medical expense deduction. An FSA can only reimburse what its own plan covers.

Where blood tests fit

Publication 502 lists laboratory fees as a medical expense when they are part of medical care. It also includes an annual physical examination and diagnostic tests by a physician, and says you do not have to be ill at the time. The IRS gives the reason in its FAQ on nutrition, wellness and general health: a physical exam qualifies because it provides a diagnosis of whether a disease or illness is present. Publication 502's own example of a diagnostic device is a blood sugar test kit used by someone with diabetes.

The deciding factor is purpose. In guidance on wearable devices added in September 2026, the IRS said a general desire to monitor or improve health is not enough to make a device a medical expense. Factors that point the other way include a medical practitioner's recommendation, symptoms, a diagnosis, abnormal test results and risk factors. That guidance covers wearables, not blood tests, but it shows where the IRS draws the line between medical care and general wellness.

Nutrition, exercise and other care: when a diagnosis matters

Many services sit on the boundary between medical care and general health. The pattern in the IRS rules is consistent: a doctor's recommendation on its own is not enough. The service has to treat a specific condition that a physician has diagnosed.

The same IRS FAQ, which applies to HSAs, FSAs, Archer MSAs and HRAs, answers several of these directly:

• Nutritional counselling qualifies only if it treats a specific disease diagnosed by a physician, such as obesity or diabetes.
• A weight-loss programme qualifies only if it treats a specific disease diagnosed by a physician, such as obesity, diabetes, hypertension or heart disease.
• A gym membership qualifies only if it was bought for the sole purpose of treating a specific disease diagnosed by a physician, or of affecting a structure or function of the body, such as a prescribed physical therapy plan for an injury.
• Exercise for general health, such as swimming or dancing lessons, does not qualify, even if a doctor recommends it.
• Nutritional supplements qualify only if a medical practitioner recommends them as treatment for a specific medical condition diagnosed by a physician.
• Special food qualifies only if it does not meet normal nutritional needs, it alleviates or treats an illness, and a physician substantiates the need. Only the cost above ordinary food counts.

What a letter of medical necessity does

When an expense counts only because of a diagnosis, you need a way to show it. A letter of medical necessity is a written note from your doctor that names the diagnosed condition and explains how the service or product treats it. HealthCare.gov, run by CMS, defines medically necessary as health care services or supplies needed to diagnose or treat an illness, injury, condition, disease or its symptoms and that meet accepted standards of medicine.

The IRS relies on the same idea in places. Publication 502 says treatment at a health institute counts only if a physician prescribes it and issues a statement that it is necessary to alleviate a disability or illness. Special food counts only when a physician substantiates the need.

A letter does not change the rules. It is evidence that an expense already meets them, and it cannot turn general fitness into medical care. Your plan administrator decides whether it needs a letter, what it must say and how long it stays valid, so ask before you pay.

HSA rules: no deadline, but keep your records

HSA money does not expire. Publication 969 says contributions remain in your account until you use them, and the account stays with you if you change employers. Distributions are tax free when they pay qualified medical expenses you incur after you set up the HSA. Money withdrawn for other reasons is subject to income tax and may face an additional 20% tax.

You must keep records showing that each distribution paid qualified medical expenses that were not reimbursed from another source or claimed as an itemised deduction. Keep them with your tax records; you do not send them with your return. And if an HSA or FSA pays or reimburses a cost, you cannot also deduct it as a medical expense on your federal tax return.

FSA rules: use it or lose it, with two possible exceptions

Health FSAs need proof for every claim. Publication 969 says you must give the plan a written statement from an independent third party showing that the expense was incurred and its amount, plus a statement that no other health coverage has paid it. For 2026, the limit on salary reduction contributions to a health FSA is $3,400, up from $3,300 in 2025.

Health FSAs are generally use-it-or-lose-it plans. Money left at the end of the plan year generally cannot be carried into the next year, and your employer is not allowed to refund it to you. A plan may soften this with one of two options. It cannot offer both, and it does not have to offer either:

• A grace period of up to two and a half months after the plan year ends. Expenses you incur during that time can be paid from the money left over from the previous year.
• A carryover of unused money into the next plan year. The IRS cap is $660 for 2025 and $680 for 2026 (Revenue Procedure 2025-32). Your plan can set a lower amount, and anything above the carryover limit is forfeited.

Check with your plan administrator first

This page explains IRS rules in general terms. It is not tax advice. For your own situation, speak to your plan administrator or a qualified tax professional.

IRS rules set the outer limits. Your plan documents set the details, and for an HSA it is your records that must show each expense qualified. Before you book a blood test or a related service, ask your plan administrator:

• Is a laboratory test from this provider an eligible expense under my plan?
• What paperwork do you need: an itemised receipt, a letter of medical necessity, or both?
• If a letter is needed, what must it say and how long does it stay valid?
• Does my FSA have a grace period or a carryover, and when is the deadline to submit claims?