I need to isolate plasma from blood for RNA extraction afterwards. Does it have to be in a cold centrifuge? Do you need in general to isolate plasma in a refirigerated centrifuge or is it only for RNA?
Collect whole blood into anticoagulant-treated tubes e.g., EDTA-treated or citrate-treated. Or add these agents in tubes before blood collection.
You may not use heparin since heparin can often be contaminated with endotoxin, which can stimulate white blood cells to release cytokines. Cells are removed from plasma by centrifugation for 10 minutes at 1,000–2,000 x g using a refrigerated centrifuge. Centrifugation for 15 minutes at 2,000 x g depletes platelets in the plasma sample.
The resulting supernatant is designated plasma. Following centrifugation, it is important to immediately transfer the liquid component (plasma) into a clean polypropylene tube using a Pasteur pipette. The samples should be maintained at 2–8°C while handling. If the plasma is not analyzed immediately, the plasma should be apportioned into 0.5 ml aliquots, stored, and transported at –20°C or lower. It is important to avoid freeze-thaw cycles. Blood samples which are hemolyzed, icteric, or lipemic can invalidate certain tests. There are commercially available tubes for blood sample collection.