What are the criteria for anemia?

Anemia is classified clinically according to the degree of decrease in hemoglobin concentration. Mild anemia is defined as hemoglobin concentration less than 120g/L, moderate anemia is defined as hemoglobin concentration between 60-90g/L, and severe anemia is defined as hemoglobin concentration between 30-60g/L. For anemia, patients should take iron and other drugs according to doctor's advice.