A concern in the forensic science community is that a contaminant profile would be mistakenly reported.  The most likely cause of contamination of evidence is from the staff involved in handling of samples.  Based on this knowledge, it is highly desirable that the laboratory maintains a staff DNA database.  Ideally, this would include everyone involved from collection to completion of analysis. This database can be assessed against any unknown profiles developed from evidentiary samples as part of data interpretation to ensure that no contamination from a staff member is mistakenly reported.

Due to legal or departmental constraints, it is recognized that some laboratories may not be able to maintain a staff database of this scope, if at all.  An alternative is for laboratories to obtain volunteer samples on a case-by-case basis where contamination is suspected.

This procedure can also be expanded to the following:

• DNA profiles from contractors who work in the laboratory area
• DNA profiles from visitors to the laboratory
• DNA profiles from employees of subcontract vendor laboratories

Back Forward