Donna has explained in reply to your previous thread. Risk of missing an antibody is very little by AB screen (by commercial cells esp 3 cell panel) vs cross match. Frequency of missing an antibody due to dosage effect in cross match is higher than missing a low frequency or private AB by AB screen. Few years ago I had a meeting with a German University Hospital Transfusion chief, he was in favour of AB Screen+IS cross match+AHG Cross match, but he had not good reasons to perform AHG cross match, just he said he did not want to leave any chance/risk. Still in some countries it is necessary to do AHG (Major cross match) beside ABS. Some of our senior (old) consultants also wants to perform ABS+IS+AHG, but they agree that AB screen+IS/Computer is sufficient.