What is a known reference sample, and how should it be collected?

A known reference sample is a DNA sample obtained from a particular individual (i.e. buccal swab from a victim or suspect). Known reference samples should be collected as buccal swabs. A buccal swab is a swabbing of the inside of a person’s cheek and gum area. A sterile swab should be used when taking a known reference sample. A minimum of two swabs should be used, and these swabs should be taken at the same time. The swabs should be allowed to air dry in a swab box or another appropriate container. The packaging should be clearly labeled with the individual's name. The buccal swabs do not need to be refrigerated. Known reference samples from the medical examiner’s office are typically submitted on a blood card.