The Cambridge Biotech HIV-1 Urine Western Blot Kit is an in vitro qualitative assay for the detection and identification of antibodies to Human Immunodeficiency Virus Type 1 (HIV-1), contained in human serum or plasma.  This more specific assay is used as a supplemental test with urine specimens that tested repeatedly reactive using a screening procedure (Calypte HIV-1 Urine EIA).