A peripheral blood leukocyte count that is consistently below 4.0 x 109/L is considered below normal and is referred to as leukopenia. Among them, neutropenia is most representative, and when the absolute neutrophil count is below 0.5×109/L, the condition is more severe and is called granulocyte deficiency.
The degree of neutropenia can be classified as mild ≥1.0×109/L, moderate (0.5-1.0)×109/L, or severe <0.5×109/L. Patients with mild neutropenia may not have specific clinical symptoms, or may only have mild discomfort such as low fever and malaise. Moderately and severely reduced patients are prone to infections and non-specific symptoms such as fatigue, weakness, dizziness, loss of appetite, etc. The common sites of infection are respiratory tract, gastrointestinal tract and genitourinary tract. For leukopenia, mild decreases generally do not require special precautions. Those with moderate deficiency have an increased rate of infection and should pay attention to prevention, maintain hygiene and remove chronic foci of infection. Severe deficiencies are prone to serious infections and should be treated with aseptic isolation and symptomatic treatment with antibacterial and immunomodulatory drugs according to the appropriate source of infection, as well as leukocyte-promoting drugs to increase the number of leukocytes in the body and reduce complications. In summary, when the absolute value of neutrophils in the body is lower than 0.5×109/L, the condition is more serious and timely measures should be taken to prevent infection and add drugs to treat various complications. More importantly, the cause of leukopenia should be clarified in a timely manner in order to achieve a radical cure.