Buccal Swabs are cotton-tipped applicators (similar to a Q-Tip) that are used to collect cheek cells from the inside of a person's mouth. The cheek cells are used for DNA testing (also referred to as DNA profiling and DNA fingerprinting). Buccal Swabbing is a non-invasive procedure that takes a few minutes. Using cheek cells is as accurate as using blood when doing DNA testing. DNA testing can be done using a variety of body fluids, e.g., blood, saliva or semen.
It can also be done using tissue collected from a personal item, like a toothbrush or razor. In criminal cases, the defendant may willingly provide DNA evidence to show that the DNA found on the victim does not belong to the defendant. In other words, if the defendant has been accused of rape he could provide DNA evidence – most likely using a Buccal Swab. His DNA profile could then be compared to the DNA in the semen collected from the victim. If the DNA did not match, it would be nearly impossible to convict him of the rape.
All 50 states require that convicted sex offenders provide a DNA sample. Forty-five states require DNA samples from all felons. For example, in California all adults arrested for any felony must provide a Buccal Swab DNA sample, and thumb and palm print impressions for the State of California's DNA (CAL-DNA) Data Bank Program pursuant to Penal Code section 296(a)(2)(C). State DNA data bases are connected to the National DNA Index System, which is run by the Federal Bureau of Investigation (FBI) for federal and state information sharing.