There are two types of hemoglobin abnormalities, one is abnormal hemoglobin concentration and the second is abnormal hemoglobin structure. Abnormal hemoglobin concentration includes increased hemoglobin concentration and decreased hemoglobin concentration. Decreased hemoglobin concentration indicates the presence of anemia, which can be caused by various diseases, including iron deficiency anemia, aplastic anemia, megaloblastic anemia, myelodysplastic syndrome, etc. Increased hemoglobin concentration can be seen in myeloproliferative diseases, such as true erythropoietic anemia, primary thrombocytosis hyperplasia. Also, chronic hypoxic diseases can have increased hemoglobin concentration and abnormal hemoglobin structure, collectively known as hemoglobinopathies. There are a variety of clinical conditions of which the most clinically significant is thalassemia. Thalassemia is a hereditary disease in which the patient develops symptoms of hemolytic anemia due to genetic alterations that result in impaired synthesis of erythrocyte peptide chains. Thalassemia is divided into two categories, α-thalassemia and Β-thalassemia, according to the abnormalities of the peptide chain structure.