Longevity

Free T4 (Thyroxine) Blood Test: Normal Ranges, ...

What Is Free T4? Free thyroxine (FT4) measures the unbound, biologically active fraction of thyroxine in the blood. Thyroxine is the most abundant thyroid hormone, produced exclusively by the thyroid...

TSH Blood Test: Normal Ranges, Causes & What Yo...

What Is TSH? Thyroid stimulating hormone (TSH), also known as thyrotropin, is produced by the anterior pituitary gland and acts as the master regulator of thyroid function. TSH stimulates the...

Thyroid Peroxidase Antibody (TPO) Blood Test: N...

What Is Thyroid Peroxidase Antibody? Thyroid peroxidase antibodies (TPO Ab, also called anti-TPO or thyroid microsomal antibodies) are autoantibodies directed against thyroid peroxidase - the key enzyme responsible for iodinating...

Thyroglobulin Antibody Blood Test: Normal Range...

What Is Thyroglobulin Antibody? Thyroglobulin antibodies (TgAb) are autoantibodies directed against thyroglobulin - a large glycoprotein produced exclusively by thyroid follicular cells. Thyroglobulin is the precursor molecule from which thyroid...

Free Testosterone Blood Test: Normal Ranges, Ca...

What Is Free Testosterone? Free testosterone is the fraction of total testosterone that circulates unbound to any protein in the blood - typically 1–3% of the total. Unlike testosterone bound...

Testosterone Blood Test: Normal Ranges, Causes ...

What Is Testosterone? Testosterone is the primary male sex hormone (androgen), though it is also produced in smaller amounts by the ovaries and adrenal glands in women. In men, the...