 QRT-PCR methods use fluorescent dyes, such as Sybr Green, or fluorophore-containing DNA probes, such as TaqMan, to measure the amount of amplified product in real time.If the targeted genetic sequence is unique to a certain GMO, a positive PCR test proves that the GMO is present in the sample.Whether or not a GMO is present in a sample can be tested by Q-PCR, but also by multiplex PCR.