Materials and methods for processing blood samples
Provided herein are materials and methods relating to cell-free DNA. In particular, the technology relates to methods and materials for the preparation and handling of blood samples for future use in applications involving cell-free DNA.
1. A method for processing a blood sample, the method comprising:
a. providing a tube comprising
an outer wall and a base defining an internal volume for containing the blood sample;
a chemical preservative disposed in the internal volume, wherein the chemical preservative one or more of metaformaldehyde, poloxamer, glycerol, propranolol, dex-propranolol, methyacrylate monomer, methyacrylate polymer, or bis-dienoyl phosphatidylcholine;
a physical separator disposed in the internal volume, wherein the physical separator substantially separates the blood sample into at least a plasma component and a blood cell component when the tube is centrifuged and prevents aspiration of the blood cell component during subsequent isolation of the plasma component from the tube; and
a blood sample disposed in the tube;
b. centrifuging the tube at a first fixed speed to separate the blood sample into at least a plasma component and a blood cell component;
c. isolating the plasma component; and
d. centrifuging the isolated plasma component at a second fixed speed to obtain further purified plasma component, wherein the first fixed speed and the second fixed speed are each independently selected from a speed ranging from 500×g to 2000×g.
2. The method of claim 1 , further comprising isolating the further purified plasma component after step d.
3. The method of claim 2 , further comprising storing the isolated further purified plasma component at a temperature of −20° C. or colder.
4. The method of claim 1 , wherein the blood cell component includes a white blood cell component and a red blood cell component.
5. The method of claim 4 , further comprising isolating the white blood cell component after step b.
6. The method of claim 5 , wherein the method further comprises storing the isolated white blood cell component at a temperature of −20° C. or colder.
7. The method of claim 1 , wherein the first fixed speed and the second fixed speed are the same.
8. The method of claim 7 , wherein the first fixed speed and the second fixed speed are each 1100×g.
9. The method of claim 7 , wherein the first fixed speed and the second fixed speed are each 1400×g.
10. The method of claim 2 , further comprising determining an amount of cf-DNA in the further purified isolated plasma component.