Patent ID: 8551707

Claim:
A method for determining the relative amount of fetal nucleic acid in a maternal plasma sample, comprising: (a) amplifying at least 10 polymorphic sites in nucleic acid obtained from a maternal plasma sample, which polymorphic sites comprise single nucleotide polymorphisms with a minor allele frequency of greater than 0.3 and are selected from the group consisting of: rs7551188, rs11247894, rs6687785, rs4487973, rs4648888, rs12089156, rs2050927, rs12125888, rs12143315, rs213624, rs660279, rs635364, rs9431593, rs11166512, rs4329520, rs454782, rs12136370, rs12759642, rs11184494, rs2454175, rs156988, rs10793675, rs1829309, rs1452628, rs4570430, rs12062414, rs7545381, rs6427673, rs10802761, rs642449, rs4839419, rs9324198, rs1192619, rs4657868, rs6426873, rs438981, rs3128688, rs4987351, rs6692911, rs6684679, rs4320829, rs4658481, rs3768458, rs860954, rs10453878, rs10753912, rs1637944 and rs4839282; (b) quantifying the relative amount of the alleles at said at least 10 polymorphic sites; and (c) expressing the relative amounts of fetal and maternal alleles as a ratio, wherein the ratio indicates the relative amount of fetal nucleic acid present in the maternal sample.