Thyroid Test

Thyroxine (T4) is a hormone made by the thyroid gland. We measure levels of Free T4, which is a key marker for thyroid function.

We also measure Thyroid-stimulating hormone (TSH) which is the pituitary (brain) hormone that controls the thyroid gland.

The thyroid gland is a butterfly shaped endocrine gland that’s located in the front part of the neck just below the Adam’s apple. The thyroid gland plays a vital role in the metabolism, development, and regulation of the human body. It uses iodine from the food we eat (an element that the body can’t make on its own) to produce the key thyroid hormones, tri-iodothyronine (also known as T3) and tetra-iodothyronine (also called thyroxine or T4). The thyroid gland also makes the peptide hormone calcitonin. The former two are what are referred to as “thyroid hormones” made by this gland and they play a crucial role influencing aspects such as the body’s weight, internal temperature, energy levels, skin, hair and nail growth among others.

Depending on the state in which the body is in, the requirement for more or less of the thyroid hormones is finely balanced. To ensure the right amount of hormonal balance, the thyroid gland relies on the pituitary gland to signal via a hormone called Thyroid stimulating Hormone (TSH) whether to release more or fewer hormones into the bloodstream. For instance, increased production of T3 and T4 may be needed to boost the body’s metabolic rate if it slows.

Thyroid blood tests usually measure TSH, T4 and sometimes T3, to assess thyroid function. T4 is usually measured as free T4 (the portion of active T4 circulating in the blood) and T3 is usually measured as free T3. The YorkTest Thyroid Test measures TSH and free T4 (FT4).
Advanced thyroid function tests also measure thyroid antibodies.

Early signs of thyroid problems include:

– Gastrointestinal problems (Diarrhoea (hyperthyroidism); Constipation (hypothyroidism))

– Mood changes (Anger, anxiety (hyperthyroidism); Depression (hypothyroidism))

– Weight changes (Weight loss (hyperthyroidism); Weight gain (hypothyroidism))

– Skin problems (Oily skin (hyperthyroidism); Dry skin (hypothyroidism))

– Sensitivity to temperature changes (Difficulty in hot weather, sweating when it’s not excessively hot, hot flashes (hyperthyroidism); Difficulty in cold weather, needing to wear extra layers inside, cold feet and hands (hypothyroidism))

– Vision changes (Watery eyes; Eye redness or dryness; Difficulty closing the eyelids; Bulging eyes)

– Hair thinning or hair loss

– Memory problems

– Lumps or nodules on the neck See a doctor if you notice a lump on the neck.

Both hypothyroidism and hyperthyroidism are prevalent forms of thyroid disease that impact millions of individuals throughout the world.
Hypothyroidism refers to an underactive thyroid gland (that does not produce enough thyroid hormone), this can be caused by autoimmune thyroid disease, thyroid cancer treatment, certain medicines, a malfunctioning pituitary gland, or the excessive intake of certain foods.

Hyperthyroidism is a condition where the thyroid gland produces more thyroid hormones than is needed by the body, an overactive thyroid gland. This can be caused by a condition called Grave’s disease (an autoimmune disorder), an enlarged thyroid gland (goitre), or thyroiditis (temporary inflammation of the thyroid gland).

No, you do not need to fast before taking a thyroid blood test unless you are also taking the YorkTest Cholesterol Test or the YorkTest Essential Health Check at the same time.