The five blood tests are the white blood cell count, white blood cell classification, red blood cell count, hemoglobin count, and platelet count. If the total white blood cell count exceeds the normal range, it suggests that the patient may have a bacterial infection, often accompanied by an increased proportion of neutrophils. Different leukocytes in the leukocyte classification express different meanings, such as an increased proportion of eosinophils, suggesting that the patient is an allergic patient, or that the patient has an allergic disease or eosinophilic disease. If the patient shows an increase in the proportion of monocytes, it suggests that the patient is accompanied by the possibility of viral infection. If the patient has a decreased red blood cell count with decreased hemoglobin in routine blood tests, this suggests that the patient may be anemic. If the patient’s platelet count, that is, the total number of platelets is reduced, it suggests that the patient’s coagulation system has problems. Therefore, the five routine blood tests are very common and meaningful laboratory tests in the clinic.