Circulating DNA and miRNA isolation

Abstract

Analysis of circulating nucleic acids undoubtedly represents a breakthrough in the diagnostic field and in predictive, preventive and personalized medicine. In order to adequately and systematically study and to transfer this approach into clinical practice, standardization of the pre-analytical steps is a crucial prerequisite. Thus, during the first pre-analytical step, it is critical to achieve nucleic acid extraction from blood cell free nucleic acid with the highest purity and yields. Optimization of isolation processes will lead to a low variation of measurements and sensitive quantification of these macromolecules that are often present at low concentration and sometimes are physically tightly associated with biological constituents in the blood. Various isolation methods are used, but ready to use extraction kits appear as a good compromise with respect to routine application, especially in a clinical setting. Improvement or high specificity of the circulating nucleic acid analysis might be possible with a better knowledge of their form and structure. The choice of the biological source (serum vs. plasma) is described in the previous chapter. Circulating DNA and micro RNA were recently applied in clinical practice; their isolation methods are here described and discussed.