The Quick-cfDNA/cfRNA Serum & Plasma Kit enables simple and efficient preparation of all circulating cell-free DNA and RNA (including protein-bound, exosomal, microRNA, and other small RNA) from serum, plasma, and other biological fluids, without using toxic phenol-chloroform or cumbersome protein precipitation and removal steps. The kit efficiently separates cell-free DNA and RNA, with option to co-elute. Cell-free nucleic acids scale linearly relative to the sample input volume up to 3 ml. Zymo-Spin™ Technology enables isolation of ultra-pure cell-free nucleic acids suitable for all subsequent analyses, such as RT-qPCR and NGS.