To determine whether the baby has anemia, routine blood tests should be performed, which can be determined by a combination of the following indicators, and not by a single indicator alone. 1. red blood cell count and hemoglobin level: the hemoglobin level is the main one, and if it is significantly lower than the normal value, it generally belongs to anemia. However, the standard value of hemoglobin level for anemia differs depending on the age of the baby, with hemoglobin <145g/L in the neonatal period, <90g/L in 1-3 month olds, <100g/L in 4-6 month olds, <110g/L in 6 months to 6 years olds, and <120g/L in 6-14 year olds. so the age of the baby is different and the criteria for determining anemia Judgment criteria are different and should be compared with the normal value of hemoglobin. If it is the red blood cell count, generally lower than (3-4) × 10^12/L is anemia; 2. MCV, MCH and MCHC: three indicators are mean red blood cell volume, mean red blood cell hemoglobin and mean red blood cell hemoglobin concentration, if MCV and MCH are significantly higher than the normal range, it means it is macrocytic anemia; if these three indicators are less than the normal value, it means it is small If the MCV and MCH are significantly higher than the normal range, the anemia is macrocytic; if all three indicators are less than normal, the anemia is microcytic hypochromic. Clinically, microcytic hypochromic anemia is more common, such as iron deficiency anemia and thalassemia.