Flow cytometric indirect immunofluorescence assay with high sensitivity and specificity for detection of antibodies to human immunodeficiency virus (HIV)

A flow cytometric immunofluorescence assay (FIFA) was developed to detect antibodies to human immunodeficiency virus (HIV) using live cell indirect immunofluorescence and analysis by flow cytometry. A panel of 107 sera, previously tested for anti-HIV antibody with the Abbott Enzyme-Linked Immunosorbent Assay test and Western blot (WB), was rescreened by FIFA. Antibodies were tested on HIV-infected and uninfected H9 cells in the FIFA. Although ELISA results indicated seven false positive results by comparison with the WB, 46 of 46 FIFA positive results tested WB positive and 61 of 61 FIFA negative results were WB negative. The results of FIFA showed 100% sensitivity and 100% specificity compared with WB. This rapid, quantitative, relatively easy assay makes FIFA an alternate confirmatory test for the presence of HIV antibodies.