Thalassemia is a hereditary hemolytic anemia caused by a defect in the synthesis of a globin chain. Approximately 13% of the population is affected, and this figure may rise to 30 - 40% among ethnic minorities, particularly in the northern mountainous region. 80% of Bac Kan population, are ethnic minorities. A cross-sectional descriptive study on students at Chu Huong Secondary School in Bac Kan province showed that the overall anemia rate among the subjects was 35.08%, of which anemia with serum iron deficiency accounted for 9.42%; the rate of thalassemia carriers was 11%; the number of children carrying the thalassemia gene was 23.48% and the α-thalassemia carrier genotype accounted for 58.06% of the total number of carriers, with two main mutations: 3.7 and SEA