White blood cell count may be lowered by radiation therapy, an infection, bone marrow damage or disorder or one of several diseases, Healthline states. These diseases include lymphoma, HIV, autoimmune disorders, lupus, and diseases of the liver and spleen.
A WBC count is typically performed if the patient reports chronic headaches, body aches, fever or chills, Healthline explains. It may also be performed as part of a complete blood count: a procedure that provides a comprehensive overview of the patient’s blood. A WBC count is useful for uncovering immune deficiencies, infections and blood or autoimmune disorders, as well as for tracking the efficacy of cancer therapies such as radiation treatment and chemotherapy.
As a WBC count is performed on a blood sample, the procedure is minimally invasive for the patient. First, the specialist performing the procedure selects a vein in the arm or the back of the hand to draw blood from. Next, the area is cleaned and an elastic band tied around the upper part of the arm, squeezing it tightly. This pushes the blood outward, making extraction from the vein quicker and easier. After the needle pierces the vein, the blood is stored in the needle’s tube, while a gauze is placed on the pierced area to contain the bleeding.