Thyroid Testing

The ATA recommends that adults start getting thyroid tests beginning at the age of 35 years and every five years after the first screening. It adds that adults who are experiencing symptoms of thyroid disease or who are considered at high risk for thyroid disease may need to be screened more frequently. Harvard Medical School says women are more likely to have low thyroid hormone levels than men and, therefore, may benefit from thyroid testing.

You may consider getting a thyroid test if you are experiencing signs and symptoms of thyroid disease. According to UC San Diego Health, the most common thyroid conditions are hyperthyroidism, hypothyroidism, and thyroid nodules.

Hyperthyroidism symptoms, according to the U.S. Department of Health and Human Services (DHHS), include:

• Weight loss
• Rapid or irregular heart rate
• Anxiety
• Irritability
• Difficulty sleeping
• Tremors in the extremities
• Increased sweating
• Muscle weakness
• Diarrhea or frequent bowel movements
• Changes in the eyes, such as redness or bulging
• Menstrual periods that are lighter or less frequent than usual

Hypothyroidism symptoms include:

• Feeling unusually cold
• Constipation
• Muscle weakness
• Weight gain
• Muscle or joint pain
• Depression
• Fatigue
• Dry hair and skin
• Slow heart rate
• Puffy face
• Hoarse voice
• Menstrual bleeding that is heavier than usual

Thyroid nodules do not always produce symptoms, says the DHHS. One way to check for a thyroid nodule is to stand in front of a mirror and look for bumps on both sides of the windpipe below your Adam’s apple. If you find a bump, swallow and watch to see whether the bump moves up and down. If it does, make an appointment with your doctor for thyroid testing.

Your doctor may order a thyroid test if you are experiencing symptoms of a thyroid condition. Some lab service providers can also perform thyroid testing without a doctor’s referral.

Thyroid testing can even be done at home using a testing kit purchased from a pharmacy or online retailer. At-home thyroid test kits usually come with everything you need to perform the test, as well as the supplies needed to send it safely to a lab.

Talk to your doctor if you think you need a thyroid test. Your doctor can help you determine whether this test is necessary based on your symptoms and a medical exam and make a recommendation accordingly.

Blood tests and imaging tests can be used to check the thyroid, reports the National Institutes of Health (NIH). Blood tests for the thyroid include the thyroid stimulating hormone (TSH), T4, T3, and thyroid antibody tests.

TSH is a hormone that tells the thyroid how much T4 and T3 it should make. A high level of TSH usually indicates you have an underactive thyroid or hypothyroidism, while a low level of TSH may indicate you have an overactive thyroid or hyperthyroidism, says the NIH.

T4 thyroid blood test

A high level of T4 in your blood could indicate hyperthyroidism, while a low level of T4 may indicate hypothyroidism. The NIH says high or low levels of T4 don’t necessarily mean you have a thyroid condition, as levels of this hormone may fluctuate with the use of medications, including oral contraceptives and corticosteroids.

T3 thyroid blood test

A T3 thyroid test may be performed if your doctor thinks you have hyperthyroidism despite having a normal level of the T4 hormone. In these instances, a T3 test may confirm the diagnosis of hyperthyroidism.

Thyroid antibody test

A thyroid antibody test may be used to diagnose autoimmune thyroid disorders such as Graves’ disease, reports the NIH. Your body makes thyroid antibodies when the immune system attacks the thyroid gland.

Thyroid imaging

Imaging procedures for thyroid conditions include ultrasound, thyroid scan, and radioactive iodine uptake test, says the NIH. Ultrasound allows your doctor to inspect thyroid nodules closely to determine whether they may be cancerous. Thyroid scans allow your doctor to examine the shape, size, and position of the thyroid gland and to look for the presence of thyroid nodules. The radioactive iodine uptake test helps your doctor evaluate the way your thyroid functions and identify the root cause of hyperthyroidism.

Thyroid blood tests

Thyroid blood tests are performed like most other routine blood tests. During a thyroid blood test, your provider will use a fine, thin needle to draw a small sample of blood from a vein in your arm. The test usually takes under five minutes, reports the National Library of Medicine (NLM). You may feel a slight sting at times the needle is being inserted and removed.

Thyroid ultrasound

During an ultrasound, your provider will have you lie flat on an exam table. Your provider will then run a device called a transducer over your neck to generate images of your thyroid. According to the NIH, an ultrasound thyroid test takes around 30 minutes.

Thyroid scan

During a thyroid scan, your provider will inject a small amount of radioactive iodine into your vein, which helps any thyroid nodules show up more clearly in photos. Then, you will lie flat on an exam table while a camera takes photos of your thyroid. This procedure can usually be performed in under 30 minutes.

Radioactive iodine uptake test

A radioactive iodine uptake test also requires you to receive an injection of radioactive iodine beforehand. Then, according to the NIH, your provider will have you sit in a chair while a device called a gamma probe is placed near the thyroid gland. The gamma probe measures the amount of iodine being collected by your thyroid to determine whether you may have Graves’ disease. This thyroid test usually only takes a few minutes to perform.

Thyroid blood tests usually do not require any special preparation. However, the NLM says you may be required to fast for several hours beforehand if you are receiving other blood tests at the same time.

Ultrasound does not require any preparation, according to the NLM. The thyroid scan and the radioactive iodine uptake test usually require you to avoid eating foods with high amounts of iodine for up to a week before your test. Additionally, your provider may have you come in up to 24 hours before your test to receive the injection of radioactive iodine. This gives your thyroid enough time to absorb the substance so it can be viewed clearly in photos during your test.