Laboratories that run forensic tests should adhere to high-quality standards and be accredited. The laboratories should engage in proficiency testing and the results from such tests made available for review. A positive control, a negative control and a reagent blank sample should be run for all tests. Inadvertent transfer of DNA, chain of custody and contamination are major areas of concern for DNA forensic evidence and could contribute to undesirable variation in a case.
Whenever possible, samples should be divided into two or more parts so that additional tests or repeat tests can be performed. If possible, any additional tests should be run by different personnel from those conducting the first test, and in a different laboratory if possible. The best opportunity for justice, for a wrongly implicated innocent person, is an independent re-test (National Research Council, 1996).
Was this article helpful?