Use of a silver-enhanced gold-labelled immunoassay for detection of antibodies to the human immunodeficiency virus in whole blood samples.

A silver-enhanced gold-labelled immunosorbent assay (SEGLISA) for the detection of antibodies to the immunodeficiency virus (HIV) in whole-blood samples is described. This new non-isotopic, non-enzymic immunoassay incorporates use of solid phase viral antigens which bind any HIV antibodies present in the test sample. The antigen/antibody complex is then detected by gold-labelled anti human immunoglobulin G (IgG) followed by silver amplification. We found that whole blood samples give false positives when using a horseradish peroxidase label, whereas the SEGLISA correctly identified 50 HIV antibody positive samples and 50 HIV antibody negative samples when using whole blood. The use of whole blood collected on filter paper is also described. The SEGLISA has good precision (CV = 7.5%) and sensitivity.