Fluorescent antibody test Fluorescent antibody test. A: In the direct fluorescent antibody test, the fluorescent dye is attached directly to the antibody that is interacting with the antigen (dark triangles) on the surface of the cell. B: In the indirect fluorescent antibody test, the fluorescent dye is attached to antibody made against human IgG. Source: Antigen–Antibody Reactions in the Laboratory, Review of Medical Microbiology and Immunology, 14e Citation: Levinson W. Review of Medical Microbiology and Immunology, 14e; 2016 Available at: https://accessmedicine.mhmedical.com/DownloadImage.aspx?image=/data/books/1792/mmi14_ch64_f007.png&sec=134512546&BookID=1792&ChapterSecID=120721269&imagename= Accessed: December 25, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved