Forensic Science Service Tasmania, 20 St. Johns Avenue, New Town, Tasmania 7008, Australia.
Forensic Science Service Tasmania, 20 St. Johns Avenue, New Town, Tasmania 7008, Australia.
Forensic Sci Int Genet. 2014 Sep;12:86-92. doi: 10.1016/j.fsigen.2014.05.003. Epub 2014 May 13.
A significant number of evidence items submitted to Forensic Science Service Tasmania (FSST) are blood swabs or bloodstained items. Samples from these items routinely undergo phenol:chloroform:isoamyl alcohol organic extraction and quantitative Polymerase Chain Reaction (qPCR) testing prior to PowerPlex(®) 21 amplification. This multi-step process has significant cost and timeframe implications in a fiscal climate of tightening government budgets, pressure towards improved operating efficiencies, and an increasing emphasis on rapid techniques better supporting intelligence-led policing. Direct amplification of blood and buccal cells on cloth and Whatman FTA™ card with PowerPlex(®) 21 has already been successfully implemented for reference samples, eliminating the requirement for sample pre-treatment. Scope for expanding this method to include less pristine casework blood swabs and samples from bloodstained items was explored in an endeavour to eliminate lengthy DNA extraction, purification and qPCR steps for a wider subset of samples. Blood was deposited onto a range of substrates including those historically found to inhibit STR amplification. Samples were collected with micro-punch, micro-swab, or both. The potential for further fiscal savings via reduced volume amplifications was assessed by amplifying all samples at full and reduced volume (25 and 13μL). Overall success rate data showed 80% of samples yielded a complete profile at reduced volume, compared to 78% at full volume. Particularly high success rates were observed for the blood on fabric/textile category with 100% of micro-punch samples yielding complete profiles at reduced volume and 85% at full volume. Following the success of this trial, direct amplification of suitable casework blood samples has been implemented at reduced volume. Significant benefits have been experienced, most noticeably where results from crucial items have been provided to police investigators prior to interview of suspects, and a coronial identification has been successfully completed in a short timeframe to avoid delay in the release of human remains to family members.
提交给塔斯马尼亚法医科学服务局（FSST）的大量证据物品是血拭子或血斑物品。这些物品的样本通常在进行 PowerPlex(®)21 扩增之前进行酚：氯仿：异戊醇有机提取和定量聚合酶链反应（qPCR）测试。在政府预算紧缩、提高运营效率的压力以及越来越强调快速技术以更好地支持基于情报的警务的财政环境下，这种多步骤过程对成本和时间框架有重大影响。已经成功地在参考样本上实施了直接用 PowerPlex(®)21 对布和 Whatman FTA™卡上的血液和口腔细胞进行扩增，从而消除了对样品预处理的要求。为了消除冗长的 DNA 提取、纯化和 qPCR 步骤，扩大该方法包括不太原始的案件血拭子和血斑物品样本的范围进行了探索。血液被沉积在一系列基质上，包括那些历史上发现会抑制 STR 扩增的基质。使用微打孔器、微拭子或两者收集样品。通过全体积和减少体积（25μL 和 13μL）放大所有样本来评估通过减少体积放大来节省进一步的财政的潜力。总体成功率数据显示，在减少体积时，80%的样本产生完整的图谱，而在全体积时为 78%。在织物/纺织品类别的血液上观察到特别高的成功率，100%的微打孔样本在减少体积时产生完整的图谱，在全体积时为 85%。在这次试验成功后，已经在减少体积的情况下实施了合适的案件血样的直接扩增。已经体验到了显著的好处，最明显的是在向警方调查人员提供关键物品的结果之前，对嫌疑人进行了采访，并且在短时间内成功完成了法医鉴定，以避免延迟将遗体归还家属。
