One aspect of the invention is a method for amplifying alpha globin genes HBA1, HBA2 and HBA12 in a single PCR tube to determine an HBA genotype of a subject. This method employs five primers selected to accurate and sensitively identify the HBA1, HBA2, and HBA12, a gene found at a higher frequency in citizens of Saudi Arabia, by accurately annealing to nucleic acids in a biological sample and simultaneously amplifying sequences encoding the alpha globin genes. This invention includes a procedure and required reagents for the amplification of alpha globin genes in a single PCR tube.