Human IgA can be used in flow cytometry, IHC, sandwich or competitive ELISAs or lateral flow assays to block non-specific binding. Goat or sheep anti-IgA can be used as secondary antibodies for indirect detection in immunoassays. They can provide an increase in sensitivity through signal amplification and greater flexibility for labeling and detection. The secondary antibody should be from a different host species as the primary antibody, but it should have the species specificity for the primary antibody. For example, if the primary antibody is sourced from rabbits, the secondary antibody should be anti-rabbit but it should be raised in a host species other than rabbit (e.g. goat anti-rabbit secondary).