I. Introduction
Our blood is made up of several components—red blood cells, white blood cells (WBCs), platelets, and plasma. Platelets are much smaller than red blood cells and WBCs. Moreover, they are actually fragments of cells made in the bone marrow. Their main function is to help clot the blood and seal the wounds. Several studies also show that the platelets have roles in inflammation and immune response [1]. Platelets also have roles in the tumor microenvironment [2], in cancer and cancer-associated thrombosis [3]. If the number of platelets becomes too low, spontaneous bleeding can occur. Even a small amount of bleeding can be dangerous, particularly if it occurs in the brain. Only 0.1% of human blood cells are categorized as WBCs; however, they carry rich information about the immunity status of the body; thus, separation of WBCs from the whole blood is a considerable issue and is substantial in clinical diagnosis.