The efficiency of DNA extraction kit and the efficiency of recovery techniques to release DNA using flow cytometry

Abstract

Lyse&Spin-QIAamp DNA Mini Kit. • About 23% of DNA is recovered using the combination of the QIAshredder and QIAamp DNA Mini kit and the Microcon® 30 column. • The extraction efficiencies of the Lyse&Spin-QIAamp DNA Mini Kit obtained by two different laboratories are similar. • The FLOQSwab™ allows releasing about 97% of the cells attached to it. Novelty Statement This research was carried out in the context of evidence evaluation considering activity level propositions when the findings are a low level of DNA obtained from touched surfaces. In such cases, knowledge of the DNA extraction kit efficiency and the efficiency of instrument to release DNA is required to evaluate the significance of DNA quantity results. Only a few studies dealt with these efficiencies. However, in these studies, the sole efficiency of the swab alone or the sole efficiency of the extraction kit alone usually remains unknown. This study aims at showing how the efficiency of DNA extraction kits and the yield of release of cells from swabs can be measured. p. 2 / 20 We also reports on the impact of the laboratory, since DNA extraction using Investigator® Lyse&Spin Basket-QIAamp DNA Mini kit from Qiagen were performed by two different persons, operating manually, from two different laboratories.

Methods for ensuring the highest DNA concentration and yield in future and retrospective trace DNA extracts

“…The results of this study are limited by the method used to estimate the exact amount of DNA available before extraction. Cellcounting is inexpensive and straightforward, but labour-intensive, and subject to human error [34]. Future work may wish to consider more extensive validation of input DNA quantities including techniques such as direct quantitative PCR of cell solutions, flow cytometry or other cell counting methods.…”

Bayesian networks and dissonant items of evidence: A case study

“…Extrapolation from published data for practical use in a case analysis can then be troublesome. Moreover, the probability assignments on other variables, such as Cleaning are subjective by nature; others, such as the Extraction efficiency are specific to the methods and kits used by each laboratory [42] and would then require a most careful analysis in order to validate the values presented in this article.…”

The use of Bayesian Networks and simulation methods to identify the variables impacting the value of evidence assessed under activity level propositions in stabbing cases

“…For the variable for the "Sampling Efficiency", we will distinguish the "swab" from the "Tapelift". In [5], the parameters Be (25,20) of the beta distribution representing the data for "Swab" condition were based on [15]. As before, we will randomly draw a limited sample (21) from that distribution to carry out the Bayesian update of our prior distribution.…”

“…It is rather easy for a laboratory to increase its knowledge base associated with some of the 427 variables involved (see [25] for example regarding the acquisition of data in relation to sampling and extraction efficiency).…”