Pediatric anemia is classified into four degrees: mild, moderate, severe and very severe, based on the amount of hemoglobin and the number of red blood cells in peripheral blood. Anemia may affect pediatric development and even cause damage to multiple organ systems and should be diagnosed by early blood tests. Pediatric anemia may manifest as pale skin and mucous membranes, profuse sweating and rapid heart rate after activities such as running or jumping, and in severe cases, palpitations and difficulty in breathing. The specific criteria are: 1. mild anemia: hemoglobin 120-90/L; 2. moderate anemia: hemoglobin 90-60g/L; 3. severe anemia: hemoglobin 60-30g/L; 4. very severe anemia: hemoglobin <30g/L. In addition, newborns with anemia can usually show pale color of face, lips and nail bed, easy irritability, crying, and disinclination to breastfeeding. There are some variations in the classification criteria: 1. mild anemia: hemoglobin 144-120g/L; 2. moderate anemia: hemoglobin 120-90g/L; 3. severe anemia: hemoglobin 90-60g/L; 4. very severe anemia: hemoglobin <60g/L. Children with mild anemia are not easily detected by parents if the clinical symptoms are relatively mild. Moderate anemia will show symptoms of anemia, such as pale face, dizziness, headache, etc. Severe anemia can affect various important organs of the child such as the heart, lungs, and brain. Extremely severe anemia may lead to heart failure or even shock in children and requires early medical attention.