NOTE: This test can only be purchased by men with suspect PSA over 4 mg/dL.  Free PSA will not be provided for PSA under 4 ng/mL.

PSA circulates through the body in two ways; bound to other proteins or by itself. Unbound PSA is called free PSA. A free-PSA test will measure the percentage of unbound PSA while a PSA test is used to measure the total of free and bound PSA in the blood. The free PSA is a defective variant of normal PSA that can no longer bind to other proteins and so circulates in the blood in the free form. Although the reason why this is the case is poorly understood - patients with prostate cancer may have lower free PSA levels than those with a benign prostate condition.

The thyroid stimulating hormone (TSH) is produced and secreted by the pituitary gland and stimulates the thyroid to produce T3 and T4. When TSH is elevated, low thyroid function may be indicated. If TSH is low it is indicative of high thyroid function. A study found that TSH was suppressed in all subjects after food, so fasting may be suggested although it is not reqired by Quest. Free T4 and Free T4 values did not change significantly after eating.

A complete blood count CBC with differential test panel measures several components of your blood including:Red blood cells, which carry oxygen, White blood cells, which fight infection, Hemoglobin, the oxygen-carrying protein in red blood cells, Hematocrit, the proportion of red blood cells to the fluid component in your blood (which correlated with blood thickness), and Platelets, which help with blood clotting. This is also called Complete Blood Count (CBC) with Differential and Platelets Blood Test

Thyroxine-binding globulin (TBG) is a globulin that binds thyroid hormones in circulation. It is one of three transport proteins (along with transthyretin and serum albumin) responsible for carrying the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in the bloodstream. Of these three proteins, TBG has the highest affinity for T4 and T3 but is present in the lowest concentration. Despite its low concentration, TBG carries the majority of T4 in the blood plasma.

Iodine, Serum/Plasma - Iodine is an essential element that is required for thyroid hormone production. The measurement of iodine serves as an index of adequate dietary intake and iodine overload, particularly from iodine-containing drugs.