Polymerase Chain Reaction or PCR, in short, is a method to identify the HIV virus as early as 1 or 2 days once the person is infected. This technique amplifies the genetic matter by RT ( Reverse transcription) enzymes induction which replicates the HIV Virus in the cell so that the virus could show up more visibly. This method can be applied in even samples which contain only minute quantities of DNA like Hair Strand, Saliva, Stool, pus, Skin Scrapes and Blood Whereas this method is mostly conducted using the Blood samples because of more reliant results.