A persons DNA is individually unique, and is contained in every single cell in the human body. Oral swab testing works by collecting cheeks cell DNA. Blood DNA testing is conducted by examining DNA extracted from blood. The DNA taken from both sources is absolutely identical, because of this neither oral swab or blood testing is more accurate then the other as both will give the same result. The principal advantage of oral swab testing and the reason for its popularity is that it allows for non-invasive and painless collection of DNA.