Neutrophil 1.6 x 10^9/L is not serious.
In general, the normal value of neutrophil count in adults is (2~8) x 10^9/L. Therefore, neutrophil 1.6 x 10^9/L is a slight decrease and is not considered serious. It may be related to uneven distribution of neutrophils in blood vessels or physiologic fluctuations (e.g., time of day, exercise, hormone levels, etc.).
If there is no history of medication, no other test abnormalities or fever, cough and other uncomfortable symptoms, it is generally not a disease, does not need special treatment, and will not be dangerous, regular review can be.
In normal life, it is recommended to exercise appropriately to improve blood circulation. Diversify your diet to ensure adequate intake of folic acid and B vitamins. Regular work and rest, avoiding labor and staying up late.