The Western Journal of Medicine recommends that patients who have a white blood cell count below 500 per microliter and signs of infection seek immediate hospitalization and antibiotic therapy. White blood cell counts below 500 per microliter qualify as severely low and can lead to death from common infections.
A normal white blood cell count is 4.500-10,000 per microliter of blood, according to MedlinePlus. One type of white blood cell, the neutrophil, helps fight infections. An adult neutrophil count below 1,700 is low, and one below 500 represents a high risk of infection. When a patient has a high risk of infection, even common bacteria that live in the mouth and on the skin can cause life-threatening infections in an individual.
Severely low white blood cell counts are usually due to an underlying condition or treatment, such as cancer, HIV/AIDS or radiation therapy, according to Mayo Clinic. Rarely do severely low white blood cell counts come as a surprise to a doctor, and the doctor is likely to take steps to protect the health of the patient. Patients with low white blood cell counts should talk to their doctors about their condition, and they should discuss its effect on their future treatment measures.