An automated method for recovering double-stranded nucleic acids from a liquid sample, comprising: a) contacting the liquid sample containing double-stranded nucleic acids with magnetic glass particles (MGPs) in chaotropic solution at a temperature between 25°C and 45°C in a vessel, thereby allowing the double-stranded nucleic acids to non-covalently bind the MGPs in solution in the vessel; b) applying a magnetic field to the vessel holding double-stranded nucleic acids non-covalently bound to MGPs in solution and removing liquid not bound to the MGPs; c) conducting a first elution step, wherein said first elution step comprises (i) contacting double-stranded nucleic acids non-covalently bound to MGPs with elution buffer having a pH of 7-10 in the vessel at a temperature between 25°C and 45°C for 5-30 minutes; (ii) applying a magnetic field to the vessel; and (iii) collecting liquid not bound to the MGPs, thereby collecting eluate; d) conducting a second elution step, wherein said second elution step comprises (i) contacting double-stranded nucleic acids non-covalently bound to MGPs with elution buffer having a pH of 7-10 in the vessel at a temperature between 25°C and 45°C for 5-30 minutes; (ii) applying a magnetic field to the vessel; and (iii) collecting liquid not bound to the MGPs, thereby collecting eluate; wherein the eluate collected in steps c)(iii) and d)(iii) comprises at least 30% double-stranded nucleic acids recovered from the MGPs of the total nucleic acids in the eluate and wherein the double-stranded nucleic acids is cell-free nucleic acid of 50-500 base pairs in length. a) contacting the liquid sample containing double-stranded nucleic acids with magnetic glass particles (MGPs) in chaotropic solution at a temperature between 25°C and 45°C in a vessel, thereby allowing the double-stranded nucleic acids to non-covalently bind the MGPs in solution in the vessel; b) applying a magnetic field to the vessel holding double-stranded nucleic acids non-covalently bound to MGPs in solution and removing liquid not bound to the MGPs; c) conducting a first elution step, wherein said first elution step comprises (i) contacting double-stranded nucleic acids non-covalently bound to MGPs with elution buffer having a pH of 7-10 in the vessel at a temperature between 25°C and 45°C for 5-30 minutes; (ii) applying a magnetic field to the vessel; and (iii) collecting liquid not bound to the MGPs, thereby collecting eluate; (i) contacting double-stranded nucleic acids non-covalently bound to MGPs with elution buffer having a pH of 7-10 in the vessel at a temperature between 25°C and 45°C for 5-30 minutes; (ii) applying a magnetic field to the vessel; and (iii) collecting liquid not bound to the MGPs, thereby collecting eluate; d) conducting a second elution step, wherein said second elution step comprises (i) contacting double-stranded nucleic acids non-covalently bound to MGPs with elution buffer having a pH of 7-10 in the vessel at a temperature between 25°C and 45°C for 5-30 minutes; (ii) applying a magnetic field to the vessel; and (iii) collecting liquid not bound to the MGPs, thereby collecting eluate; wherein the eluate collected in steps c)(iii) and d)(iii) comprises at least 30% double-stranded nucleic acids recovered from the MGPs of the total nucleic acids in the eluate and wherein the double-stranded nucleic acids is cell-free nucleic acid of 50-500 base pairs in length. (i) contacting double-stranded nucleic acids non-covalently bound to MGPs with elution buffer having a pH of 7-10 in the vessel at a temperature between 25°C and 45°C for 5-30 minutes; (ii) applying a magnetic field to the vessel; and (iii) collecting liquid not bound to the MGPs, thereby collecting eluate;