10X Phosphate Buffered Saline (PBS) is a concentrated stock solution and should be diluted appropriately with distilled, deionized water or equivalent to its final working concentration which is 1X for this kit. SHEEP RED BLOOD CELLS (RBC) 10% Washed Pooled Cells - R405-0005 should be diluted in 1X PBS to 0.05% concentration. Anti-SHEEP Red Blood Cell (RBC) (RABBIT) Antibody - 213-4139-0002 binds and thus hemagglutinate Sheep RBCs when used at a dilution range of 1:25-1:50. An antibody mediated hemagglutination control is useful as a qualitative index for the integrity of the RBCs in the assay. Further serial dilutions up to 1:400 can be included in the assay if an independent or antibody-based control is required in the assay.