|
STEP 10
KNOWN SALIVA SAMPLE |
| Saliva
Specimen |
| Although ABO
factors are found in everyone’s blood, approximately 75-
80% of the population also demonstrate ABO factors in
their body secretions (semen, saliva, vaginal secretions,
etc.). Such persons are called ABO secretors. The
remaining 20-25% are called non-secretors, because they
lack ABO factors in their secretions. |
| In the ABO
analysis of secretion mixtures, such as semen and vaginal
secretions, the ABO type of the victim must be identified
in order to evaluate properly the blood type of the other
contributor. A dried sample of known saliva and the known
liquid blood sample are used to determine the ABO secretor
status of the victim. |
| Filter paper
discs should be used for the collection of the saliva
sample. Unlike gauze pads, filter paper air dries quickly.
Also, the loose weave of some gauze pads tends to disperse
the saliva, making it more difficult to analyze. |
| Saliva
Specimen Collection Procedure |
| It is
important that this specimen not be contaminated by
outside elements. Therefore, the victim should not smoke
or have anything to eat or drink for at least 15 minutes
prior to this procedure. |
| If there has
been oral contact during the sexual assault the victim may
wish to wash out her/his mouth. Please perform this
procedure as soon as possible for the victim’s comfort. |
| The examiner
should collect a saliva sample by using a filter paper
disc that is already packaged in a small, pre-sealed
envelope. The victim should manually place the disc in
his/her mouth, saturating it with saliva. Labeling
information on the envelope is then to be completed. |
| Victims
should be reminded not to chew the disc; moistening it for
a few seconds usually is sufficient. Victims should also
be instructed to remove the disc with their own fingers.
Because slightest contamination from another person’s
secretions may be detected by the forensic analysis, the
disc must not be removed by anyone other than the victim
unless a hemostat is used. |
| When dry, the
disc is to be completely inserted back into the envelope
and the envelope sealed with tape. |
