A qBiomarker Copy Number Assay designed to target AR, which is on the X-chromosome, was tested against 4 cell line DNAs containing 1 copy (XY, Coriell NA13619), 2 copies (XX, Coriell NA01921), 3 copies (XXX, Coriell NA03623) and 4 copies (XXXX, Coriell NA11226) of X-chromosome. Chromosomal aberrations had been previously identified by cytogenetic methods. A control assay, targeting a stable, multi-copy region in the human genome, was used to normalize the amount of DNA input. ΔΔCTmethod was used to calculate the gene copy number, using XX (Coriell NA01921) as a 2-copy reference. The assay was tested against each sample in quadruple replicate reactions, and a t-test was performed.