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.

Includes liver and kidney function, glucose and electrolytes

The serum iron test measures the amount of iron in your blood. The total iron-binding capacity (TIBC) test looks at how well the iron moves through your body.

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.