title: The forensiX evidence collection tube and its impact on DNA preservation and recovery.
abstract: Biological samples are vulnerable to degradation from the time they are collected until they are analysed at the laboratory. Biological contaminants, such as bacteria, fungi, and enzymes, as well as environmental factors, such as sunlight, heat, and humidity, can increase the rate of DNA degradation. Currently, DNA samples are normally dried or frozen to limit their degradation prior to their arrival at the laboratory. In this study, the effect of the sample drying rate on DNA preservation was investigated, as well as a comparison between drying and freezing methods. The drying performances of two commercially available DNA collection tools (swab and drying tube) with different drying rates were evaluated. The swabs were used to collect human saliva, placed into the drying tubes, and stored in a controlled environment at 25°C and 60% relative humidity, or frozen at -20°C, for 2 weeks. Swabs that were stored in fast sample drying tubes yielded 95% recoverable DNA, whereas swabs stored in tubes with slower sample drying rates yielded only 12% recoverable DNA; saliva stored in a microtube at -20°C was used as a control. Thus, DNA sampling tools that offer rapid drying can significantly improve the preservation of DNA collected on a swab, increasing the quantity of DNA available for subsequent analysis.
authors.affiliation: Confarma France SARL, Zone Industrielle Canal d'Alsace, 68490 Hombourg, France.
authors.forename: Alex M
authors.initials: AM
authors.lastname: Garvin
authors.forename: Ralf
authors.initials: R
authors.lastname: Holzinger
authors.forename: Florian
authors.initials: F
authors.lastname: Berner
authors.forename: Walter
authors.initials: W
authors.lastname: Krebs
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hostettler
authors.forename: Elges
authors.initials: E
authors.lastname: Lardi
authors.forename: Christian
authors.initials: C
authors.lastname: Hertli
authors.forename: Roy
authors.initials: R
authors.lastname: Quartermaine
authors.forename: Christoph
authors.initials: C
authors.lastname: Stamm
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001419:Bacteria / Q000254:growth & development; D004247:DNA / Q000302:isolation & purification*; D003890:Desiccation; D044707:Forensic Sciences / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D011309:Preservation, Biological / Q000295:instrumentation* / Q000379:methods*; D012463:Saliva / Q000378:metabolism / Q000382:microbiology; D013048:Specimen Handling / Q000295:instrumentation* / Q000379:methods*; D013997:Time Factors
chemical_list: D000255:Adenosine Triphosphate; D004247:DNA