HbA2 is -

Human Hb exists in a number of types which differ slightly in the structure of their globin moiety. HbA2 is minor Hb in the adult red cell with structural formula alpha 2 delta 2.Alpha with 141 aminoacid and delta with 146 aminoacids.It is present in very small amounts at bih and reaches adult level during first year of life. Increases in some types of thalasssaemia and occasionally occurs in megaloblastic anaemia.It may be reduced in iron deficiency anaemia. Alpha 2 beta 2 is HbA Alpha 2 gamma 2 is HbF(foetal Hb) Beta 2 gamma 2 doesnot exsist But zeta 2 gamma 2 is embryonic Hb - poland Ref:de Gruchy's Clinical hematology in medical practice 6th adapted edition.Page no.121 Ref Robbins 9/e pg 422