Leukopenia is a laboratory-diagnosed state in which the leukocytes (i.e., white blood cells) circulating in the blood drop below the minimum normal value. A typical adult lower bound is 4,500 cells per microliter, subject to laboratory variations. .
It may be due to a decrease in all subtypes of cell, or a decrease in one of the more prevalent types without compensating increases in the others.
The more severe the leukopenia, the less defense the body has against infection. Overwhelming infection can itself cause leukopenia, but it is not the only cause. Exposure to ionizing radiation, including doses used in therapy, can cause it. Leukopenia is common as a result of cancer chemotherapy with antineoplastic agents.
- WBC count, Medline Plus