cell-free DNA from urine - (Dec/08/2019 )

Hi,

What is the best method to separate ow molecular weight DNA from high molecular weight DNA from urine. Would anyone have a protocol to cell-free DNA from urine. eve tried 2 kits and none of them give a good yield. 

I have had good results with Qiagen kits (though only from serum and not from urine). Have you tried this kit: https://www.qiagen.com/us/products/discovery-and-translational-research/dna-rna-purification/dna-purification/cell-free-dna/qiaamp-circulating-nucleic-acid-kit/#orderinginformation ?

There are a couple ways to separate DNA by molecular weight. Gel purification and magnetic beads are probably the best options. I would recommend magnetic beads, since the mass of cfDNA recovered is often so low you will never see it on a gel. However, I would question whether it is really necessary to separate cfDNA by molecular weight for most experiments.