The World of Forensic Laboratory Testing

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Testing in Cases of Abuse

Sexual Abuse Cases
Routine testing in alleged sexual assault cases can include DNA testing in addition to tests for pregnancy and sexually transmitted infections (STIs) such as syphilis, hepatitis B and C, gonorrhoea, chlamydia, and HIV. When done within a few hours of the incident, these tests provide information about the victim's health prior to the alleged assault, not health status after the incident. Due to the lag time between the initial exposure and the technical ability to obtain a positive test result, some of these tests may be controversial. Testing may be repeated six weeks to six months after the incident to help determine if the incident resulted in pregnancy and/or infection.

If the victim doesn't remember events around the time of a sexual assault, samples from the victim may be tested for "date rape drugs", including flunitrazepam (RohypnolTM) and gamma-hydroxybutyrate (GHB). Other tests may include those for alcohol and drugs of abuse. Evidence of intoxication can be used to discredit the victim in court.

Child Abuse
In suspected child abuse cases, laboratory evidence can help ascertain if an underlying health problem may be the true reason for suspicious bleeding or bruising. If a child has numerous bruises yet no history of significant trauma, a panel of tests to exclude bleeding and clotting disorders like von Willebrand disease or another clotting factor deficiency (factor VIII and IX deficiencies) may be performed. Evidence of such a problem could exclude the possibility of child abuse.

When it is suspected that a child has been sexually abused, samples may be collected for testing that may include DNA tests and tests for sexually transmitted infections as described above. Detecting the presence of an STI may aid in evaluating whether sexual abuse had taken place.

Other laboratory tests that may be useful when evaluating tissue injuries, such as abdominal, internal organ injuries, include liver function tests (alanine aminotranferase and aspartate aminotransferase), pancreas tests (amylase and lipase), and testing for blood in urine. A positive stool test for blood (guaiac test, faecal occult blood test, FOBT) can point to rectal bleeding caused by abdominal or anal trauma.

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