One of the biggest challenges faced by crime scene investigators is improper transportation and preservation of DNA samples.
Improper collection and handling of any type of evidence can introduce foreign contaminants (like a technician’s own DNA, fibers, or trace particles) onto the sample. Where DNA evidence is concerned, the potential for contamination or degradation is even greater.
One of the reasons DNA evidence is so easily compromised is that environmental conditions like direct sunlight and heat can break down the chemical structure of DNA.
Additionally, improper storage of a moist sample (in a plastic bag, for example) can promote the growth of mold and bacteria which can degrade a sample, and ultimately, compromise the integrity of an entire case.
Another reason DNA evidence is so easily compromised is because samples of DNA evidence are often so tiny that lab technicians need to use a method called PCR (polymerase chain reaction) technology to replicate or copy the sample to generate enough for testing.
If other DNA is present, you risk replicating the contaminant’s DNA as well as the suspects, thereby compromising the integrity of the sample.
That’s why it’s so important to use only approved specimen collection, transportation, and preservation methods and to choose the best tools possible.
Traditional forensic wisdom holds that moist DNA samples should collected with a flocked, foam, or cotton tipped swab and allowed to air dry, then packed in either separate collection envelopes or “swab boxes.” These boxes can then be placed inside a coin envelope or paper bag for transportation to the lab.
But there might be a better way. In recent years, filtered air-breathable (FAB) swab and transport systems have gained popularity. Puritan’s breathable Tyvek® filter covers holes, allows air in and keeps contaminants out, prohibiting mold growth during transport.
But improper handling isn’t the only challenge crime scene investigators and forensic lab technicians face. Equally important is the careful labeling of all collected evidence.
Puritan's FAB dry transport systems eliminate the need for clunky swab boxes and also contain labels with tamper evident seals that allow investigators to record the following information:
Documented by
Date/Time
Agency
ID No.
Location
Name
Remark
This all-in-one solution can help minimize the number of tools in your crime scene investigation kit, plus provide you a more intuitive and accessible way to label and store evidence during transportation.
Want to learn more about how to choose the right tools for DNA specimen collection at crime scenes? Download our free flowchart!
SOURCES:
http://www.nij.gov/topics/forensics/evidence/dna/research/pages/compromised-evidence.aspx
http://www.crime-scene-investigator.net/evidenc3.html
http://www.crime-scene-investigator.net/collect.html
http://www.crime-scene-investigator.net/print/blood-print.html
http://www.forensicmag.com/articles/2013/02/properly-packaging-evidence