Thyroid hormone- Free thyroxine (FT4)


  • Results within 24 hours

  • Blood draw included

FT4 can detect whether or not the thyroid is functioning properly. It aids in the identification of hypothyroidism and hyperthyroidism. The test may also be used to aid in the evaluation of someone with with an enlarged thyroid gland. It may also help in the diagnosis of female infertility.

What are the symptoms of an overactive and underactive thyroid?

Overactive Thyroid (Hyperthyroidism)

  • Heat sensitivity
  • Tremors
  • Sweating
  • Heart palpitations
  • Weight loss
  • Problems sleeping
  • Enlarged thyroid gland

Underactive Thyroid (Hypothyroidism)

  • Tiredness
  • Depression
  • Constipation
  • Weight gain
  • Muscle cramps and weakness
  • Brittle hair or nails
  • Sensitivity to cold

What does a Thyroid Thyroxine (FT4) test measure?

Our Thyroid Hormone – Free Thyroxine (FT4) test measures the levels of thyroxine (FT4) in the blood, low T4 levels often indicates hypothyroidism, whereas higher levels of T4 can be seen as hyperthyroidism.

Who should get tested?

Anyone who suspects they may have either an underactive or overactive thyroid should get tested, you also may be recommended by your doctor to take a test on this basis.

How is an underactive thyroid treated?

Hypothyroidism is usually treated through hormone replacement therapy, by taking a tablet called levothyroxine daily, this replaces the thyroxine hormone which has decreased production.

Treatment through tablets may not be given if the symptoms are mild enough to not warrant medication, this may mean that a test has to be repeated every few months to monitor hormone levels in case levothyroxine needs to be prescribed.