Metabolism Matters: Understanding the Thyroid Function Test
More than 12% of the U.S. population will develop a thyroid condition during their lifetime. That might be you, and you might very well might have to take a thyroid function test. If you’re wondering what exactly that entails, you’ve come to the right place.
Whether your doctor has ordered a thyroid function test for you and you’re wondering what to expect or you’ve recently gotten your results back and want to learn more, stick around.
We’re going to dive into the details of the thyroid function test from start to finish.
What Is a Thyroid Function Test?
A thyroid function test, first and foremost, is a blood test. This means that your physician or their assistant will have to draw blood in order to perform their tests and retrieve their data. Once they’ve drawn your blood, they’ll be able to look at a number of factors to assess your thyroid function.
Primarily, they’ll be looking at a number of different hormones that your thyroid produces in order to help your body function. These are triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH).
T3 and T4 help your body control its temperature, heart rate, growth, and weight. Thyroid-stimulating hormone is the hormone that helps communicate to the thyroid itself when to produce T3 and T4 and when to stop.
A thyroid function test examines the levels of these hormones and helps determine whether your thyroid is functioning normally.
When Would I Need a Thyroid Function Test?
Your physician may order a thyroid function test if you’re exhibiting symptoms of hyperthyroidism or hypothyroidism. These are both conditions that indicate that your thyroid is operating outside of its normal range.
If you have hyperthyroidism, this means that your thyroid hormone levels are too high. You might be having symptoms such as weight loss, sweating, quick heartbeat, or trouble sleeping.
If you have hypothyroidism, this means that your hormone levels are too low. Symptoms of this condition can include weight gain, fatigue, being cold all the time, hair thinning, or mood changes like depression.
You may also need a thyroid function test if you are already on a thyroid medication and your doctor wants to check how well it’s working.
Do I Need to Prepare for This Test?
Since a thyroid function test is a blood test and does not involve general anesthesia, there is little that you have to do to prepare in advance for it.
In some cases, however, certain medications might interfere with your results. Consult with a doctor if you suspect that this might be true for you, and follow their guidance if they instruct you to stop taking medications ahead of time.
For your ease and comfort, it might also be a good idea to wear a short-sleeved or loose shirt on the day of your test. This will give your medical team easy access to your arm to speed along the process of drawing blood.
Understanding Thyroid Function Test Results
Usually, the first levels tested for are your thyroid-stimulating hormone levels. In adults, a normal range for TSH is between 0.4-4.5 milliunits per liter (mU/L). When your TSH levels are outside of this range, it can indicate a thyroid disorder.
When your TSH is elevated, this points to hypothyroidism. When it’s low, this indicates hyperthyroidism. If either of these is the case, your physician will test for T3 or T4.
If your TSH is low and your T3 or T4 levels are high, this supports a diagnosis of hyperthyroidism. And if your TSH is high and your T3 or T4 levels are low, this supports a diagnosis of hypothyroidism.
Is There Anything That Could Affect My Test Results?
Thyroid hormones are in flux, and so there are a number of different factors that should be taken into account when interpreting the results from a thyroid function test. Some of these factors cannot be changed and should simply be accounted for. Others could affect results in such a way that another test might be needed.
Age, for example, can impact the results of a thyroid function test. TSH levels usually increase naturally as we age, and so this should be kept in mind when you receive your results.
TSH levels also tend to be higher in the evening, so if a thyroid function test was performed at this time of day and returned higher-than-normal results, it might be worth running another test.
As mentioned earlier, medications can also sometimes affect the hormone levels detected in a thyroid test. Any estrogen supplement, often found in birth control pills, can make it seem as though T3 and T4 levels are higher than they actually are.
Thyroid hormone levels also change throughout pregnancy. There are actually different recommended normal ranges for each trimester to account for these changes.
Diagnosis of Thyroid Conditions
If the results of your thyroid function test indicate that you have a thyroid condition, your physician will guide you through the next steps necessary. It’s most important to remember that thyroid conditions are treatable, usually through medication.
It can sometimes take a few months in order to adjust to your dosage and see the necessary changes in the levels of your thyroid hormones. Changing your diet, taking supplements, and making healthy lifestyle changes can also support the treatment of a thyroid condition.
Thyroid conditions, however, should not go untreated. Those who don’t take steps to address these conditions face higher risks of heart disease, osteoporosis, and stroke. A thyroid function test will help alert you to any possible risk factors.
Testing for Optimal Health
Performing tests like the thyroid function test can help you have all of the information about your body in order to best take care of it. You now know when you might need this sort of test and even how to interpret the results so you can make the right choices for your health.
If you’re looking for a blood testing facility to trust with your thyroid function tests, explore our services today.