Bad blood is too generalized and may be due to abnormal blood counts or abnormal liver or kidney function. Taking routine blood tests as an example, we will discuss the indicators commonly used in clinical practice, which mainly include red blood cells, white blood cells and platelets. 1. Red blood cells are mainly concerned with the presence of anemia and the type of anemia, and include indicators such as red blood cell count and hemoglobin value. The normal value of hemoglobin is 120-160g/L for adult men, 110-150g/L for adult women, and 170-200g/L for newborns. 2. The main indicators of white blood cells are the counts and proportions of neutrophils, eosinophils, basophils, lymphocytes and monocytes. The white blood cell count is (4-10) x 10^9/L in adults, (15-20) x 10^9/L in newborns, and (11-12) x 10^9/L in 6-24 months. The normal values of classification percentages are 0%-5% for neutrophil rod-shaped nuclei, 50%-70% for lobulated nuclei, 0.5%-5% for eosinophils, 0%-1% for basophils, 20%-40% for lymphocytes, and 3%-8% for monocytes. 3. Platelets, on the other hand, are related to the hemostatic function, and the normal value of the count is (100-300)x10^9/L. In addition, other conditions can also lead to the so-called bad blood, should go to the hospital in time for examination, after clarifying the cause of the disease, under the guidance of the doctor for appropriate treatment.