The Instant-View® PSA (Prostate Specific Antigen) serum test is an initial qualitative screening test to detect PSA concentration equal to or higher than 4 ng/ml in serum within 4-7 minutes. Prostate Specific Antigen is secreted by the epithelial cells of the acini and ducts in the prostate. Normal total PSA concentration in human serum is 0.1-2.6 ng/ml. Reports have shown that elevated levels of serum PSA is the most useful tumor marker in diagnosis of prostate cancers. The cut-off point is generally agreed to be 4 ng/ml. The Instant-View® PSA serum test is for healthcare professional use only and is available for export only.