The course of chronic granulocytic leukemia is relatively long, as it is a type of chronic leukemia. Its onset is gradual, and its natural course includes four stages: asymptomatic phase, chronic phase, accelerated phase, and blast crisis phase. Most patients seek medical attention and are diagnosed only after symptoms appear, with very few patients discovering blood abnormalities during physical examinations or blood tests conducted for other reasons. At this point, the spleen may already be mildly enlarged, or not enlarged at all. In the early stages of the disease, some patients may experience an absolute increase in basophilic granulocytes. When the white blood cell count is less than 20×10^9/L, there is a decrease in neutrophil alkaline phosphatase activity in peripheral blood, and this decreases further as the disease progresses. When the white blood cell count exceeds 40×10^9/L, the spleen can be felt below the ribs. Between 30 and 90×10^9/L, a range of related clinical symptoms may appear.