Alpha thalassemia major Hemoglobin H Constant Spring Hemoglobin H disease Hydrops fetalis due to alpha thalassemia Severe alpha thalassemia Triple gene defect alpha thalassemia Use additional code, if applicable, for hydrops fetalis due to alpha thalassemia (P56.99) Excludes1: alpha thalassemia trait or minor (D56.3) asymptomatic alpha thalassemia (D56.3) hydrops fetalis due to isoimmunization (P56.0) hydrops fetalis not due to immune hemolysis (P83.2)
