There's a difference between direct and indirect fluorence. Direct fluorence involves using only 1 antibody (e.g. primary antibody) conguated to a fluorence marker. With indirect fluorence, you're using an unlabelled primary antibody with a secondary antibody (which is primed against the primary antibody) conguated to a fluorence marker. With a indirect influorence, you're trying to achieve a stronger signal. If you're tagging your antibody with a fluorence, then it is immunofluorence. Whether its in- or direct immunofluorence depends on which antibody (primary or secondary) is bound to the fluorence marker. The ELISA assay is ex. of using indirect. Hoped this helped. 😎 😎