Representative QPCR amplification plot of male DNA in G-PBMCs of a female donor. The x-axis represents the number of cycles of a PCR reaction, and the y-axis is fluorescence intensity over background. As the number of cycles increases, smaller DNA quantities amplify. Each sample is tested for β-globin (measure of total DNA) and DYS14 (measure of male DNA), with quantitative results assessed by the intersection of the amplification plots with the threshold.