hba2 is 5.8% high, generally consider that it may be caused by thalassemia or other diseases, not too serious. 1. Thalassemia: hba2 generally refers to hemoglobin a2, occupying 2.5% to 3.5% of the total hemoglobin of the human body, so the hba2 value is 5.8% high, need to receive routine blood tests. Observe whether the hemoglobin, the average volume of red blood cells and the average hemoglobin volume of red blood cells are reduced, if the reduction is obvious, it is necessary to further accept the thalassemia gene test, if the gene is abnormal, the diagnosis can be confirmed. 2. Other diseases: besides thalassemia, other diseases, such as certain unstable hemoglobinopathies and megaloblastic anemia, may also cause high hba2. It is recommended that patients need to go to regular hospitals to receive further examination, according to the results of the examination, treatment under the guidance of specialists.