Prevalence of antibodies to a new histo-blood system: the FORS system.

Background: In 1987, three unrelated English families were reported with a putative blood subgroup called A. Swedish researchers later found evidence leading to abolishment of the A subgroup and establishment instead of the FORS blood group system (System 31 - ISBT, 2012). It is important to know the prevalence of antibodies in order to make the best decisions in transfusion medicine.