Serological typing for the classical ABO blood groups is routinely performed using anti-A and anti-B antisera of polyclonal or monoclonal origin, which are able to distinguish four phenotypes (A, B, AB, and O). Modern molecular biology methods offer the possibility of direct ABO genotyping without the need for family investigations. Typing can be done with small amounts of DNA and without detection of blood group molecules on the surface of red blood cells. We developed a system of eight polymerase chain reactions (PCR) to detect specific nucleotide sequence differences between the ABO alleles O-1, O-2, A(1) A(2), and B. PCR amplification using sequence-specific primers and detection of amplification products by agarose gel electrophoresis is one of the fastest genotyping methods and is easy to handle. With our method we tested the A(1,2)BO(1,2) genotypes of 300 randomly chosen persons out of a pool of platelet donors and found the results to be consistent with ABO glycosyltransferase phenotypes. We also identified a presumably new ABO allele, which may be the result of a crossing-over event between alleles O-1 and A(2). (C) 1996 by The American Society of Hematology.
