Patent ID: 8532936

Claim:
A method for determining the presence or absence of a fetal chromosomal aneuploidy in a maternal test sample obtained from a pregnant human, said sample comprising a mixture of fetal and maternal nucleic acid molecules, said method comprising: (a) preparing a sequencing library from said mixture of fetal and maternal nucleic acids in said maternal sample; (b) massively parallel sequencing said fetal and maternal nucleic acids in said sequencing library to obtain sequence information for said fetal and maternal nucleic acids in said sample; (c) receiving said sequence information in a computer-readable medium; (d) using computer-readable instructions: (i) identifying from said sequence information a number of sequence tags for a chromosome of interest and a number of sequence tags for at least two normalizing chromosomes; (ii) using said numbers of sequence tags to calculate a first normalizing value and a second normalizing value for said chromosome of interest; and (iii) comparing said first normalizing value for said chromosome of interest to a first threshold value and comparing said second normalizing value for said chromosome of interest to a second threshold value to determine the presence or absence of a fetal aneuploidy in said sample.