In alpha thalassemia intermedia, anemia is moderate, with a decreased hemoglobin and red blood cell count. The MCV and MCHC are decreased. The RDW is increased due to red blood cell anisocytosis and poikilocytosis. RBC morphology shows slight hypochromic microcytosis with codocytes (target cells), schistocytes (schizocytes), and basophilic stippling. Reticulocytes are moderately increased.
Hemoglobin electrophoresis demonstrates abnormal patterns in both adults and neonates.
Adults:
- HbA - decreased
- HbA2 - decreased
- HbF - normal to decreased
- Hb H - 2–40% (beta chain tetramers)
Note: Neonates: 10–40% Bart's (gamma chain tetramers), Hb H inclusions are frequently seen. Bone marrow demonstrates erythroid hyperplasia.
