Using our RCL buffers for the lysis of erythrocytes from human whole blood, yields intact white blood cells free of red blood cells for further applications, particularly for DNA and RNA isolation of white blood cells. Most blood cells are red blood cells, which lack nuclei and possess no DNA. Therefore, the lysis using proper buffer followed by centrifugation steps eliminate the red cells and concentrates the nucleated white blood cells. Our RCL Buffers eliminate the need for hazardous organic extractions or chaotropic agents.