Font Size Thyroid Hormone Tests Thyroid hormone tests are blood tests that check how well the thyroid gland is working. The thyroid gland makes hormones that regulate the way the body uses energy.
THYROID LAB VALUESH (Thyroid Stimulating Hormoone) Test is performed to assess the activity of the thyroid gland. It involves measuring the concentration of thyroid-stimulating hormone (TSH) in the blood serum. TSH is secreted by the pituitary gland and stimulates the thyroid gland to produce hormones.
It is increased in hyperthyroidism and in euthyroid states characterized by increased TBG. Occasionally, hyperthyroidism will not be manifested by elevation of T4 (free or total but only by elevation of T3 (triiodothyronine).
Low T4 blood levels are seen in people who have had their thyroid surgically removed, who have an under-active pituitary gland or a non-functioning hypothalamous, kidney or liver disease, or cancer.
The United States Preventive Services Task Force recommends that all newborns be tested for congenital hypothyroidism. 1 Thyroid hormone blood tests include: Total thyroxine (T4). Most of the thyroxine (T4) in the blood is attached to a protein called thyroxine-binding globulin.
The thyroid gland stores these thyroid hormones and releases them as they are needed. Thyroid hormones are needed for normal development of the brain, especially during the first 3 years of life.
High T4 blood levels are seen in people with infection of the thyroid gland, thyroid cancer, or Grave's disease. High levels are normally seen during hormone replacement therapy or during normal pregnancy and does not indicate disease.
It is also seen in hyperthyroidism. Decreased T3 uptake (increased TBG) may occur due to the effects of exogenous estrogens (including oral contraceptives pregnancy, acute hepatitis, and in genetically determined elevations of TBG.
Decreased levels are found in hypothyroidism, normal pregnancy, and hyperestrogenis status. This test measures the amount of thyroxine-binding globulin (TBG) in the patient's serum. When TBG is increased, T3 uptake is decreased, and vice versa.
When T4 and T3 are too high, TSH secretion decreases, when T4 and T3 are low, TSH secretion increases. Normal Adult Range: miliIU/L back to top. DISCLAIMER This web site's goal is to provide you with information that may be useful in attaining optimal health.
Screen newborns to find out if the thyroid gland function is normal. A condition called congenital hypothyroidism can prevent normal growth and development and cause other severe problems, such as intellectual disability, if it is not treated soon after birth.
Free T3 Index FT3I 80-180 Radioactive iodine uptake RAIU 10-30. Serum thyrotropin TSH uU/ml Thyroxine-binding globulin TBG 12-20 ug/dl T4 1.8 ugm. TRH stimulation test Peak TSH 9-30 uIU/ml at 20-30 min Serum thyroglobulin l.
Less than 1 of the T3 is unattached. A T3 blood test measures both bound and free triiodothyronine. T3 has a greater effect on the way the body uses energy than T4, even though T3 is normally present in smaller amounts than T4.
Therefore, if thyrotoxicosis is clinically suspect, and T4 and FTI are normal, the test "T3 -RIA" is recommended (this is not the same test as "T3 uptake which has nothing to do with the amount of T3 in the patient's serum).
Free thyroxine (FTI or FT4). Free thyroxine (T4) can be measured directly (FT4) or calculated as the free thyroxine index (FTI). The FTI tells how much free T4 is present compared to bound T4.
This unbound T4 is called Free T4; this is the T4 available to be used by the body. Protein blood levels will affect the amount of Free T4. A measurement of free T4 is more accurate for diagnosing thyroid function, and is mainly used to diagnose how well the thyroid is functioning.