It is easy to mistake red blood cells for white blood cells. Clinicians and researchers must lyse red blood cells from a sample of blood in order analyze and count the white blood cells that remain. Red blood cell lysing techniques can result in the incomplete lysis of red blood cells. Additionally, a large population of patients have hard-to-lyse red blood cells. Existing solutions for hard-to-lyse samples either adversely alter the cells via chemical fixation or require the use of dyes. There is a need for a technique, such as this, that is capable of helping researchers and clinicians more effectively identify white blood cells in the presence of red blood cells without lysing red blood cells, without altering cells, and without dyes.