Avoid strenuous exercise, emotional stress, and measurements in overly high or low environments before checking blood counts, all of which can cause an increase in the number of white blood cells in the peripheral blood and affect the judgment of the results. White blood cells have a diurnal variation, with lower white blood cell counts during quiet and rest, higher after activity and eating, lower in the morning and higher in the afternoon. For long-term monitoring of white blood cells, blood should be collected at the same time and under the same conditions as possible. Don’t drink a lot of water before the routine blood test, after drinking a lot of water blood dilution will affect the results of judgment. The three routine tests, including blood routine, urine routine and stool routine, are the most basic and important tests, and have been listed as mandatory tests for many years. They can reflect a variety of diseases, such as anemia, coagulation defects, inflammation, leukemia can be detected through routine blood screening. Blood routine is extremely important, and precautions must be taken before testing blood routine to avoid affecting the results of blood routine.