Both Original Medicare and Medicare Advantage cover the full cost of thyroid testing, but you’ll usually need to meet your deductible first.

The thyroid is your body’s thermostat and key regulator of many bodily functions.

The chances of having a low or high rate of thyroid function — hypothyroidism or hyperthyroidism, respectively — increase as you age, according to a 2019 review.

This is especially relevant for Medicare beneficiaries, who are generally over age 65.

Medicare has four parts that cover certain services. Part B is the portion that usually pays for medical, preventive, and diagnostic services. This is also true when you need thyroid testing.

As with many Medicare services, you’ll usually need to meet certain criteria for thyroid test coverage:

  • You must have symptoms that could be linked to your thyroid function.
  • A doctor will need to certify that the test is medically necessary.
  • You must get the test from a Medicare-approved laboratory.

Some of the reasons you might need a thyroid test include:

  • You have a goiter or nodule on your thyroid.
  • You’re experiencing symptoms of hypothyroidism (too little thyroid hormone).
  • You’re experiencing symptoms of hyperthyroidism (too much thyroid hormone).
  • You’re already taking a thyroid medication, and your doctor needs to assess how well it’s working.

The thyroid and the hormones it produces can affect almost every system in your body. A doctor may order thyroid hormone testing for a range of symptoms, including:

  • abnormal cardiac rhythms
  • high cholesterol levels
  • mental health disorders
  • skin disorders

You typically won’t pay anything for Medicare-covered laboratory tests as long as your doctor orders the tests and you’ve met your deductible. It’s important you ensure that the lab doing the testing accepts Medicare.

Thyroid testing involves taking a blood sample. Your doctor may:

  • perform the blood test in their office
  • send you to a specific laboratory
  • send you to a hospital laboratory

If you have a Medicare Advantage (Part C) plan, your policy must cover at least as much as Original Medicare (parts A and B). However, each plan may have its own deductible or copayment rules.

You may also need to go to an in-network provider or laboratory that accepts both Medicare and your specific Medicare Advantage policy.

If your doctor orders testing more often than Medicare coverage allows (typically, two thyroid tests per year), you may have to get prior authorization to ensure Medicare coverage.

To qualify for covered thyroid tests, you’ll need a Medicare-approved doctor to say there’s a reason for the thyroid test and to send you to a Medicare-approved laboratory for testing.

In most instances, Medicare will cover up to two thyroid laboratory tests per year for clinically stable patients — that is, those without severe or significant symptoms.

However, Medicare may cover more frequent testing for patients who:

  • have had thyroid cancer
  • are adjusting their thyroid medications
  • start to have a new onset of possibly thyroid-related symptoms

One way to ensure that Medicare will pay for your thyroid testing is to check Medicare’s care compare tool.

You can enter information about the professional performing the test and the facility to make sure they participate with Medicare.

Medicare will usually cover the costs of thyroid testing once you’ve met your deductible.

Your doctor must certify the test is medically necessary, and you must go to a Medicare-approved laboratory.

You may have limitations on how many thyroid tests you can get within the year.