This testing involves blood and gene tests to check for alpha-globin gene changes. Hemoglobin H disease (HbH) is a form of alpha thalassemia in which. HbH disease tends to be more severe in patients with the. HbH disease should be considered in infants or children with mild-to-moderate microcytic hypochromic hemolytic anemia and hepatosplenomegaly. This test is very sensitive in detecting Hb H in α-thalassemia syndromes.