True-Stain Monocyte Blocker is a non-antibody based blocking buffer shown to reduce non-specific binding of tandem fluorophores commonly used in flow cytometry like PE/Dazzle 594, PE/Cy5, PE/Cy7, PerCp/Cy5.5, APC/Cy7 and APC/Fire 750 to monocytes and macrophages. The True-Stain Monocyte Blocker ensures no artefactual staining due to these fluorophores while not affecting desirable monocyte staining in the assay.