AdvanBlock-PF is a protein-free blocking buffer, optimized for reducing non-specific background in fluorescent and chemiluminescent Western blots. It acts quickly for shorter membrane incubation times, efficiently prevents non-specific binding, and stabilizes the fluorescence of secondary antibody conjugates. AdvanBlock-PF can reduce background when used with primary antibodies that have a high degree of cross-reactivity with protein blockers such as BSA, casein or milk protein. With low-quality primary antibodies that may require protein-based blocking agents, BSA or non-fat dry milk can be dissolved directly in the AdvanBlock-PF solution used to dilute the antibody. Provided as a 5X concentrate.