The LiveSure^TM PSA Serum Rapid Test utilizes two-site sandwich immunoassay technology and specific antibodies to PSA for the qualitative detection of PSA in human serum.  The LiveSure^TM PSA Whole Blood Rapid Test utilizes two-site sandwich immunoassay technology and specific antibodies to PSA for the qualitative detection of PSA in human whole blood.  Prostate specific antigen (PSA) is a serum protease found only in prostate epithelial cells of the acini and ducts.  Normal PSA concentration in human serum is 0.1-2.6 ng/ml. Reports have suggested that elevated levels of serum PSA is the most useful tumor marker in the diagnosis of prostate cancers.  The LiveSure^TM PSA Rapid Test is an immunochromatographic rapid test designed to detect human PSA at concentrations as low as 4 ng/ml within five minutes.