Streamlining the laboratory processes
is certainly desirable but will not necessarily address the issue that the number of samples, together with variable success rates, often leads to a backlog of items awaiting analyses [10]. When the biological stain is easily identifiable and rich in DNA (e.g. visible blood, saliva or semen stain) submitted items are likely to yield informative STR results [11] and [12]. However, GSK1210151A in the absence of any prior information, submitting items for DNA analyses becomes increasingly subjective and can result in an increased number of items being submitted which do not return a result [13] and [14]. The submission of items of this kind requires a degree of training and personal experience, which varies between individuals and enforcement agencies [11] and [12]. Currently, the first indication that DNA is present on a submitted evidence item occurs after sample examination, DNA extraction and quantification.
The hands-on time required to go through this process and generate an STR profile can take as little as 8–10 h, although in many instances the enforcement authority will not receive results for several weeks or months, with costs being incurred even if samples fail. Moving to an objective submission policy see more would enable a forensic laboratory to select specific samples for analysis, saving time and resources whilst improving the success rates of submitted items and reducing the number of items awaiting analyses. A similar model is already employed with presumptive biological tests [15], [16] and [17]
and recent work has described the utility of screening for DNA using melt curve analyses [8]. Here we present the developmental validation of the ParaDNA® Screening System developed by LGC Forensics, an instrument for use outside the laboratory designed for the detection of human DNA on forensic evidence items. Validation experiments were designed to address guidelines laid out by the Scientific Working Group on DNA Analysis Methods (SWGDAM) [18]. Experiments to characterise the performance of the ParaDNA Screening System were performed http://www.selleck.co.jp/products/Paclitaxel(Taxol).html at LGC Forensics, with the inter-laboratory reproducibility trials performed in collaboration with Florida International University (FIU) and the University of Central Florida (UCF). The data presented here indicates the utility of performing presumptive DNA testing by trained DNA analysts in a laboratory or by non-specialist enforcement officers prior to item submission. The validation described below characterises keys aspects of the ParaDNA Screening System. The data can be used to determine critical factors in the screening process and determine the limitations of the technology. The ParaDNA Screening System comprises the following: The ParaDNA Screening Unit (Life Technologies®: 4484402) is the instrument used to run the ParaDNA Screening Test (Electronic Supplementary Material Fig. 1a).