(thÃ»r'mÄ«'Én) An electrically charged particle or ion that is emitted by a heated conducting material. The electrons emitted from the cathodes of electron tubes (such as cathode ray tubes) are thermions.
A low white blood cell count (leukopenia) is a decrease in disease-fighting cells (leukocytes) in your blood. Leukopenia is almost always related to a decrease in a certain type of white blood cell (neutrophil). The definition of low white blood cell count varies from one medical practice to another. In general, for adults a count lower than 4,000 white blood cells per microliter of blood is considered a low white blood cell count. For children, that threshold varies with age.
1 Leukopenia-a decrease in the total number of white blood cells (WBC), which may lead to low white blood cell count. 2  Neutropenia-a decrease in the number of neutrophils, one type of white blood cell, which may lead to low white blood cell count.ow Blood Counts. Includes: Low red blood cell count, Low white blood cell count, Low platelet count, Infection-prevention guidelines for immunosuppressed patients. Other words you may hear: 1  Myelosuppression-a decrease in the production of blood cells, which may lead to low blood count.