Some dye-labeled fluorescent antibody conjugates used in cell surface staining of live cells often exhibit non-specific binding in monocytes and macrophages. CytoWatch™ QZ100 Monocyte Blocking Reagent is a non-antibody-based blocking solution that is optimized to blocking the non-specific background of cyanine-based dye conjugates. It can effectively eliminate non-specific staining of monocytes and macrophages by cyanine dye conjugates (such as PE/Cy5, PE/Cy7, APC/Cy7, PE/Dazzle™ 594, APC/Fire™ 750, PE/Alexa Fluor® 647, PE/Alexa Fluor® 750, APC/Alexa Fluor® 750, PE/iFluor® 647, PE/iFluor® 750 and APC/iFluor® 750). The reagent has no impact on the specific surface staining of live lymphocytes, monocytes, and granulocytes.