Leukemia patients can have significantly lower or higher leukocytes. Patients with significantly lower leukocytes tend to be those with hypoproliferative leukemia. For leukemia patients with significantly elevated leukocytes, the leukocytes can be as high as 100×10^9 cells/L or more, at which point it is called leukocyte stasis. Patients with leukocyte stasis are in critical condition and may suffer from acute cardiovascular accidents, hemoptysis, and life-threatening respiratory and cardiac arrest at any time. Patients with leukocyte stasis should not be treated with chemotherapy immediately, but should be pretreated to reduce the tumor load appropriately before chemotherapy to prevent the occurrence of acute renal failure.