Dear Mohammad,

actually I fear that answering this would lead to some pages of text. You probably do not have access to Peter Issit´s book "Applied blood group serology" (4th edition), which includes some 20 pages answering your problem, and some tables summarizing the serological rections of A and B subgroups?

For clinical decision on transfusion you do not necessarily need the differentiation (just give group 0 erythrocytes and AB plasma if you cannot decide wether your patient truely is A or B). Are you trying to solve this problem for clinical or for scientific reasons? How often do these subgroups exist in Iran? Here in Germany, we do not see those on a regular basis (I have seen some 100.000 blood groups during the last 10 years). So we do not have a routine installed for such patients.

Actually, the easiest thing to do would be SSP-PCR.

Dear Mohammad,

ABO subgroups are identified by various techniques depending upon the available resources. The different methods include serological differentiation, adsorption and elution, saliva studies and molecular methods. However when compatible blood is required, it is important that the component is selected according to the presence or absence of corresponding antibodies in the serum reactive at 37C.

At our institution we perform to all donors and receptors reverse grouping. Ideally with commercially available red cells group A1, A2 and B. This gives us a certainty, at least for A2, which is the most common to encounter. The only problem would be if you are faced with an A2 patient with anti-A1 which, on reverse grouping, he or she will appear to be group 0. In this case you could acertain the group doing direct grouping with anti-A1 anti-serum (from dolichus biflora lectin) . At our institution we produce red cells for reverse grouping in the lab, in a media that lasts aproximately 21 days. Always do the typing in tube, which is better read than in plaque and include 4 or more group A in the pool of A cells to include, at least, one A2.