Calculating the odds of two, three, and four HLA antigen matches

The odds of finding two, three, and four HLA antigen matches between organ or tissue donors and potential recipients can be easily and rapidly determined. To calculate the odds requires three items: a programmable calculator, a list of the HLA and ABO antigen phenotype frequencies of donor and potential recipient populations, and a list of HLA antigens excluded from transplanting. The advantages to the patient, to the medical staff, and to the laboratory staff of knowing the odds of HLA antigen matching are discussed.