The original way of DNA testing is through a blood sample commonly known as DNA blood testing which is a very common practice even today with the more simple versions of DNA testing available. Because the blood needs to be separated in a centrifuge to separate the red blood cells that lack DNA from the rest of the blood cells that do contain DNA this method of blood DNA testing is not the most efficient means of testing and can often be the most expensive.

Blood is also used for the process of DNA profiling which is a technique used by the American law enforcement agencies to establish who the victim of a crime was or to establish who was present at a crime seen during the incident. The DNA blood testing can be used in all the normal DNA testing such as paternal DNA testing plus the ancestry DNA testing.