White blood cells help fight infections in the body by attacking pathogens, such as bacteria and viruses, after they invade the bloodstream. Healthline states that these cells are formed in the bone marrow and circulate throughout the bloodstream to fight and attack pathogens.
According to Healthline, there are five major types of white blood cells. These include neutrophils, lymphocytes, eosinophils, monocytes and basophils. All five of these white blood cells have specific functions and target specific types of pathogens. White blood cells can be measured by laboratory tests to determine if a patient has a health issue. A low or high white blood cell count may indicate that a patient has a blood disorder.