White blood cells 3.0 × 10⁹/L suggests leukopenia, which is not too serious for the time being, and it is recommended to consult the hospital early to clarify the cause of leukopenia and then treat it aggressively. Leukocytes 3.0 × 10⁹ / L, below the normal range (4 to 10) × 10⁹ / L, the patient may have immunocompromised, prone to co-infection. The condition is not too severe at this time, and if the white blood cells are below 2.0 × 10⁹/L or granulocyte deficiency occurs, it is more dangerous. It is necessary to pay attention to the presence of fever, cough, diarrhea, frequent urination and other symptoms, check C-reactive protein, calcitoninogen, blood sedimentation and other indicators of infection, and regular monitoring of blood routine. If the combination of serious infection or white blood cells continue to fall, it suggests that the condition is serious, if necessary, need to improve the bone marrow aspiration to clarify whether there is a blood system pathology. It is recommended that the patient should clarify the cause of leukopenia under the guidance of the physician at an early stage, and target treatment.