Cross-adsorption is a purification process that eliminates members that bind to off-target species of immunoglobulins (IgG). A cross-adsorbed secondary antibody is one that has gone through this purification process. Although this is an optional step, it is highly desirable as it reduces species cross-reactivity and increases specificity.  Using cross-adsorbed secondary antibodies can effectively prevent cross-reactivity in your assays.

Using cross adsorbed secondary antibodies is particularly useful for minimizing high background, non-specific binding, and multiplexing cross-reactivity with other primary antibodies and secondary antibodies when performing multiple labeling experiments or working with multiple primary antibodies.