Rapid method for isolating extracellular nucleic acids

The method according to one or more of claims 1 to 10, in particular claims 1 and 9, wherein step a) has one or more of the following characteristics:

• i) the first pH is below the pKa value of a protonatable group of the anion exchange groups of the solid phase;
• ii) at least one acidifying reagent and/or compound, preferably an acidic solution, is added to the sample to adjust the first pH;
• iii) the first pH is 6.5, preferably 56;
• iv) the first pH lies in a range selected from 4 to 6.5, 4.5 to 6.5, 5 to 6.5 and 5 to 6;
• and/or
• v) the sample makes up at least 90%, at least 95% or at least 97% of the volume of the binding mixture.

A method for isolating extracellular nucleic acids from a sample which is or is derived from a body fluid, preferably selected from blood, plasma or serum, wherein for isolation extracellular nucleic acids are bound to a solid phase carrying anion exchange groups, wherein said method comprises the following steps:

• a. binding the extracellular nucleic acids to the solid phase in a binding mixture at a first pH≦6 which allows binding the extracellular nucleic acids to the anion exchange groups of the solid phase;
• b. separating the solid phase with the bound extracellular nucleic acids;
• c. optionally washing the extracellular nucleic acids;
• d. eluting the extracellular nucleic acids from the solid phase at a second pH which is higher than the first pH that was used for binding the extracellular nucleic acid to the solid phase;
• e. isolating the extracellular nucleic acids from the eluate.