Though, in most cases, thyroid disorders are not medical emergencies, they can cause worrisome symptoms that interfere with your bodily functions and several aspects of your life. Whether your thyroid is overactive (hyperthyroidism) or underactive (hypothyroidism), a thyroid issue can cause fatigue, depression, restlessness, nervousness, anxiety, sensitivity to extreme temperatures, weight gain or weight loss, dry and brittle hair and nails, and other changes.
If you begin to experience one or several of the symptoms of a thyroid disorder for no discernible reason, your doctor may recommend some tests. However, because the symptoms of thyroid disorders can be easily confused with other conditions, diagnosis is often difficult. It typically requires several tests and exams, some of which are more telling than others. If your doctor suspects a thyroid condition, they may recommend the following:
Of these three types of exams, blood tests are the most accurate.
One of the most definitive ways to diagnose thyroid disorders is through a thyroid blood test. Thyroid blood tests can measure the amount of thyroid hormone in the bloodstream and, therefore, determine how well the thyroid is functioning. These blood tests are done by taking blood from a vein in your arm and asses for the following:
Thyroid blood tests are unique from standard blood tests in that they detect disorders typically associated with hyper- and hypothyroidism. Those include Grave’s disease, thyroiditis, goitre, Hashimoto’s disease, thyroid cancer and thyroid nodules. Below are the specific types of thyroid blood tests your doctor may run.
TSH is a hormone that the pituitary gland produces and that regulates the levels of thyroid hormones, including T3 and T4, in the bloodstream. The TSH test is typically the first test that a doctor will run if he or she suspects thyroid dysfunction in a patient. This is because hyperthyroidism is characterized by low levels of TSH, while hypothyroidism is associated with high levels of the hormone. If TSH levels are abnormal, the next step a physician may take is to assess the thyroid hormone levels directly.
Persons who live with hypothyroidism have low T4 levels, whereas persons with hyperthyroidism have high levels of the hormone. If your doctor suspects either condition, they may measure T4 levels.
FT4 tests measure the amount of free thyroxine in the bloodstream. As with the T4 hormone, high levels of FT4 may indicate hyperthyroidism, while low levels of FT4 may be indicative of hypothyroidism.
Though T3 tests may help diagnose some cases of hypothyroidism, they are most helpful in diagnosing and determining the severity of hyperthyroidism. This is because elevated levels of T3 typically indicate an overactive thyroid.
Free triiodothyronine naturally bind T3 proteins. Elevated levels of this hormone often indicate hyperthyroidism.
Unfortunately, these blood tests alone are not enough to diagnose thyroid conditions. If the blood tests come back abnormal, your physician may recommend additional testing to make a more accurate diagnosis. Below are additional blood tests your doctor may recommend.
Calcitonin tests are tests that diagnose medullary thyroid cancer and C-cell hyperplasia, both of which are rare thyroid disorders.
Thyroid antibody tests can help identify the presence of various autoimmune conditions that are caused by the thyroid. These conditions include but are not limited to thyroglobulin antibodies, microsomal antibodies, thyroid receptor antibodies, and thyroid blocking immunoglobulins.
This test is used to diagnose the inflammation of the thyroid (thyroiditis) and to monitor the treatment of thyroid cancer.
When measuring blood test results, your doctor will refer to ranges for each individual test. It is important to note that, while health organizations cite healthy ranges, healthy ranges differ for each individual. For this reason, it may give you peace of mind to consult with your doctor regarding your particular ranges.
Blood tests are by far the most definitive means of detecting and diagnosing thyroid disorders. However, most doctors are hesitant to rely on them alone, particularly if blood tests do not reveal a definitive cause of a thyroid disorder. To compliment the findings from a blood test, your doctor may perform an imaging test. Common types of imaging tests use to diagnose thyroid conditions are ultrasounds, thyroid scans and radioactive iodine uptake tests.
An ultrasound is a type of imaging procedure that transmits high frequency sound waves throughout the body to produce an image on a computer screen. The computer records the echoes from the sounds, which are inaudible to the human ear, and transcribes them into photographic or video images. Ultrasounds can be used to detect several issues throughout the body, including thyroid issues. However, in terms of thyroid conditions, they are most effective at detecting and more closely examining nodules.
A thyroid scan is a test that uses a small amount of radioactive iodine to more closely examine the thyroid. Through a thyroid scan, doctors can assess the size, shape and position of the thyroid gland. Due to the detail a thyroid scan can reveal, this type of imaging is often helpful in diagnosing the cause of hyperthyroidism and thyroid nodules.
The radioactive iodine uptake test is a test in which you swallow a small amount of radioactive iodine in capsule or liquid form. When you swallow iodine, your thyroid “takes it up” from the blood to make thyroid hormones, hence the name of the test. Approximately four to six hours after swallowing the liquid or capsule, your doctor will place a gamma probe on your neck near the thyroid gland for the purposes of measuring how much iodine your thyroid took up.
If your thyroid took up a large amount of iodine, it is indicative that you have either Grave’s disease or nodules. This test is often used to diagnose the causes of hyperthyroidism and/or to test how well the thyroid is functioning.
Though the least telling of diagnostic tests, most doctors start with a physical exam when they suspect thyroid disorders. If you express symptoms of a thyroid issue, your doctor may feel your neck for growths or enlargement of the thyroid. Regardless of if your doctor detects an enlargement, they may proceed with blood and imaging tests to confirm or rule out these suspicions.
If you develop symptoms of a thyroid disorder, or if your doctor suspects you have a thyroid issue, they may begin the path to diagnosis with a physical exam of your thyroid. However, a combination of blood tests and imaging tests are ultimately what your doctor will need to make an accurate diagnosis.