A secondary standard is a reference standard that is not an intimate sample such as intravenous blood or buccal swabs (swab from the interior cheek). Secondary standards are normally items that have used by the person such as a toothbrush, used dental floss, shaving razor and or a cut from a suspects hand. We generally do not like to use these items as standards because we cannot always ensure that these items came from the person in question. If an appropriate standard is available we will always request that over a secondary standard. In circumstances where an appropriate standard is not available, such as missing persons, mass disasters or interred bodies, we will consider using a secondary standard.