Low white blood cell counts may occur when patients have conditions that interfere with bone marrow functioning or conditions like cancer, viral infections and autoimmune disorders, according to Mayo Clinic. Severe infec... More »

A low white blood cell count, called leukopenia, may be caused by bone marrow problems, autoimmune disorders such as lupus, diseases involving the liver or spleen, certain viral illnesses or severe bacterial infections, ... More »

A congenital or autoimmune disorder, cancer, a viral infection, an overwhelmingly strong infection, or certain drugs may cause a low white blood cell count, Mayo Clinic advises. Damage to bone marrow, which produces whit... More »

Low white blood cell counts are commonly caused by viral infections, conditions that cause depleted bone marrow, severe infections, and certain medications that eradicate white blood cells, according to Mayo Clinic. Spec... More »

www.reference.com Health Medical Ranges & Levels

High blood cell counts can be a result of a condition that increases the bone marrow's production of white or red blood cells, according to Mayo Clinic. White blood cell production increases when the body needs to fight ... More »

Low platelet count can be caused by acquired or inherited conditions, which may cause the body's bone marrow to decrease platelet production, according to the National Heart, Lung, and Blood Institute. The body may destr... More »

Normal red blood cell counts are usually between 3.9 and 5.03 trillion cells per liter for women or between 4.32 and 5.72 trillion cells per liter for men, reports Mayo Clinic. Normal white blood cell counts fall between... More »