Common Diagnostic Tests for Thyroid Problems

Thyroid problems can occur when production of thyroid hormones either increases or decreases. A thyroid gland producing too much thyroid hormone is called hyperthyroidism. When the thyroid produces too little of the hormone, the condition is called hypothyroidism. More discussions about these two thyroid conditions in my health article "Common Thyroid Problems."

Thyroid problems may be difficult to diagnose based on symptoms alone because thyroid problem symptoms may be similar to other health conditions. To confirm the diagnosis, the doctor or healthcare provider would likely recommend several diagnostic tests. These diagnostic tests may also be used to detect the cause of thyroid problem.

The common diagnostic tests for thyroid problems include a thyroid stimulating hormone test, T₃ and T₄ test, and thyroid autoantibody test.

Thyroid stimulating hormone test. The most common test for thyroid problems is the thyroid stimulating hormone (TSH) test and probably would be the first test that a doctor performs. In TSH test, a sample of blood is taken from the patient. The healthcare provider will then measure the levels of TSH in the blood. When TSH levels are found to be high, this means that the person is suffering from hypothyroidism and if the reading is below normal, it means the person has hyperthyroidism.

The TSH blood test is the most accurate test for thyroid activity today. It is also used as a screening tool for newborn infants for a type of thyroid problem called congenital hypothyroidism.

TSH is a hormone produced by the pituitary-a small gland located in the brain. This hormone stimulates the thyroid gland to produce and secrete thyroid hormones to meet the body's needs.

When a thyroid problem is determined, the doctor may also employ other tests to confirm the diagnosis and to look for the cause of the condition.

T₃ and T₄ test. This test measures the levels of T₃ and T₄ hormones in the blood. A reading of above normal levels indicate that a person has hyperthyroidism and a reading below normal means that the person has hypothyroidism.

Triodothyronine (T₃) and thyroxine (T₄)are thyroid hormones produced by the thyroid gland. They play a role in metabolism, normal brain development, and normal growth among others. Among the two, thyroxine is, by far, the most common thyroid hormone.

Thyroid stimulating antibody test. This test is used to look for the presence of autoantibodies in the thyroid. If autoantibodies are present, this could probably pinpoint the cause of the condition. Autoantibodies are antibodies produced by the immune system when a person has an autoimmune disease. Autoimmune diseases occur when the body's immune system mistakenly attacks normal tissues, in this case, the thyroid gland.

Two conditions that can cause thyroid problems where autoantibodies can be detected are Hashimoto's disease and Grave's disease. These two conditions have different effects on thyroid function. Hashimoto's disease can cause hypothyroidism while Grave's disease causes hyperthyroidism.

Some doctors may also recommend other diagnostic testing procedures, such as the radioactive iodine uptake test and a thyroid scan, which can also be used to determine the cause of the condition.

Sources:

Hypothyroidism. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

Hyperthyroidism. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).