The hematologic features of novel coronavirus pneumonia vary slightly depending on the period of infection in which it occurs. In early mild infections, the changes in blood work are often insignificant, the white blood cell count is normal, and the ratio of various cells is within the normal range. When the novel coronavirus infection is 1-2 days old, signs similar to bacterial infection may appear, with a mildly elevated white blood cell count, an elevated granulocyte count, and a slightly elevated granulocyte ratio of about 75%. After 3-4 days of novel coronavirus infection, the blood changes of viral infection begin to appear, with a decrease in the total white blood cell count, a decrease in the granulocyte ratio, less than 50%, and a slightly higher lymphocyte ratio, about 45%. When the infection is severe, the typical blood picture of novel coronavirus infection appears, which is characterized by normal white blood cell count, high granulocyte ratio, often greater than 80%, decreased lymphocyte ratio, decreased absolute lymphocyte count, and in critical cases, decreased platelet count.