The LiveSure^TM PSA Semi-Quantitative 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 Semi-Quantitative Whole Blood Rapid Test utilizes two-site sandwich immunoassay technology and specific antibodies to PSA for the qualitative detection of PSA in human serum.  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 Semi-Quantitative Rapid Test is an immunochromatographic rapid test designed to detect human PSA at concentrations both lower than and greater than or equal to 4 ng/ml within ten minutes.  The rapid test has a built-in reference band designed to detect PSA specifically at 4ng/ml while not interfering with test results.  This reference band serves as a semi-quantitative reference for band intensity.  If results have a stronger intensity than the reference band, the PSA concentration is greater than 4 ng/ml or if test results have a weaker intensity than the reference band, the PSA concentration is weaker than 4 ng/ml.