Estimating paternity index from HLA-typing results

A procedure is described for estimating the chance of paternity from HLA-typing results. Phenotypes consisting of HLA-A and HLA-B antigens are divided into four groups. For each group, formulas have been derived to calculate the chance of passing a specific haplotype; those for common phenotypes have been predetermined and compiled into concise tables. Consequently, the paternity index can be derived in four simple steps. In reporting, paternity index is best expressed in percentages as relative chance of paternity and nonpaternity. In this way, the positive and negative aspects of estimation are both spelled out.