Do You Need To Take a Thyroid Function Test?

Submitted on March 27, 2012
Thyroid disorders can wreak havoc with your metabolism & are easy to miss. Tests are hence essential for a diagnosis.
Do You Need a Thyroid Function Test?

When Is a Thyroid Function Test Necessary?

Thyroid function tests are tests that are used to gauge the state of your thyroid gland and how well it is working. There are different types of tests such as blood tests to determine the levels of thyroid hormones such as T3, T4, TSH and thyroid scans. The latter is a nuclear medicine test involving radioactive iodine and imaging to examine the structure and functioning of the thyroid gland.

T3 or Triiodothyronine is a thyroid hormone that plays an important role in the body's metabolism. A blood test to measure the levels of this hormone in your blood is useful for determining thyroid function. Along with these levels, it is also useful to measure the levels of other hormones such as T4 or Thyroxine and TSH or thyroid stimulating hormone. The levels of these three hormones can reveal a better understanding of the functioning of the thyroid gland. For example, there are certain cases of hyperthyroidism that lead to elevated T3 levels with T4 levels remaining in the normal range.

You may be asked to take a Thyroid function test if the doctor suspects that you have a thyroid disorder. These include:

  • Hyperthyroidism - An overactive thyroid gland
  • Hypothyroidism - An underactive thyroid gland
  • Disorders of the pituitary gland - Hormones secreted by this gland affect the functioning of the thyroid gland
  • Thyrotoxic periodic paralysis - A condition where high levels of thyroid hormones cause episodes of muscle weakness
  • Thyroid nodules

Your doctor's recommendation to get a thyroid function test will depend on a tentative diagnosis of your condition based on the symptoms that you are experiencing. At times the symptoms may be minor, such as chronic fatigue or unexplained weight gain. These will depend on the underlying thyroid disorder.

Symptoms of Hypothyroidism

  • Fatigue and exhaustion
  • Depression
  • Inability to concentrate and brain fog
  • Excessive weight gain that cannot be attributed to any other cause
  • Dry and itchy skin
  • Dry, coarse or thinning hair
  • Feeling cold in the extremities
  • Constipation
  • Muscle cramps
  • Increased flow during periods
  • Frequent periods
  • Miscarriage
  • Inability to conceive

Symptoms of Hyperthyroidism

  • Nervousness and irritability
  • Profuse sweating
  • Brittle hair
  • Weakness in the upper arms and thighs
  • Tremors in the hands
  • Panic attacks
  • Rapid heartbeat, palpitations
  • Insomnia
  • Increased frequency of bowel movements
  • Unexplained weight loss
  • Lighter flow and less frequent menstrual periods

These symptoms may or may not indicate a thyroid condition. Your doctor will advise you on the need for a thyroid function test based on your symptoms.