Leukopenia is best defined as?

Leukopenia is defined specifically as a decrease in the number of white blood cells, which are crucial components of the body's immune system. A normal range of white blood cell count typically falls between 4,500 to 11,000 cells per microliter of blood, and a count below this range indicates leukopenia.

This condition can result from a variety of factors, including bone marrow disorders, autoimmune diseases, severe infections, or the influence of certain medications and treatments, such as chemotherapy. A reduced white blood cell count can lead to an increased risk of infections, highlighting the importance of understanding and identifying this term in medical contexts.

In contrast, an increase in white blood cells would be referred to as leukocytosis, which is not the correct interpretation of leukopenia. A normal white blood cell count would indicate a healthy immune system without the harms associated with leukopenia, and an increase in red blood cells pertains to a completely different condition, known as polycythemia. Therefore, the definition of leukopenia is unambiguously tied to a decrease in white blood cells.