Low HBA2 is usually indicative of anemia, commonly iron deficiency anemia, and thalassemia usually has normal or elevated HBA2. 1. HBA2 is hemoglobin A2, a type of human hemoglobin. Normal human body has three kinds of hemoglobin: hemoglobin A, hemoglobin A2, and hemoglobin F. Among them, hemoglobin A2 accounts for about 2%~3% in peripheral blood. A decrease in this indicator usually indicates anemia, such as iron deficiency anemia, iron granulocytic anemia, and hereditary HbF syndrome. 2. In thalassemia, hemoglobin A2 is usually normal or high. alpha thalassemia light hemoglobin A2 <2.5%, heavy hemoglobin hemoglobin A2 >4%. However, it is difficult to make a definitive diagnosis based on this indicator alone, so it is recommended that you consult your doctor in a timely manner and complete the examination under the guidance of your physician.