Plasma derived Serum (PDS) - How to get plasma from serum? (Jan/26/2007 )
Hello,
i have frozen rabbit plasma. The problem now is i must get Serum out of this Plasma. The plasma is unique and very much worth. The lab we got the plasma from did not know that we needed serum instead of plasma. So what can i do? Celluars like plattelets are removed already, how best to activate the rest of the clotting kaskade to remove all of the coagulation factors?
I've anyone could suggest me a solution i would very very grateful!
Greetings,
Benedikt
Plasma is whole blood collected into a tube containing an anti-coagulant. Serum is whole blood collected in to a plain tube. Both are spun to separate the cells from the liquid. The anti-coagulant in the plasma sample stop it clotting whereas the serum sample does clot and the fibrinogen formed in that process is removed. I don't think you can back track.
Some (many) analytes can be measured in either sample. Lithium heparin causes least interference with most assays. If you are measuring electrolytes be careful what anti-coagulant was used (EDTA binds calcium, potassium or sodium oxalate obviously add electrolyte to the sample. What are you working on and what methods are you using? (Plasma isn't good for electrophoresis due to the fibrinogen). Maybe we'll be able to wor out if you can use plasma.
Thank you for your immediate answer and your suggestions. The problem is I need the serum to isolate polyclonal antibodies from and the antibodies in the plasma are unique as I said before. So is there any easy way to activate the fibrinogen in the plasma? I think plasma contains Prothrombin, so maybe I can use Factor Xa to start clotting? But where should I get Factor Xa from rabbits or can I use human Factor Xa also?
Thank you in advance.
Some (many) analytes can be measured in either sample. Lithium heparin causes least interference with most assays. If you are measuring electrolytes be careful what anti-coagulant was used (EDTA binds calcium, potassium or sodium oxalate obviously add electrolyte to the sample. What are you working on and what methods are you using? (Plasma isn't good for electrophoresis due to the fibrinogen). Maybe we'll be able to wor out if you can use plasma.
If the polyclonals you are after are involved in the clotting I don't think you can recover successfully. I'm not sure that the science would be publishable. If they aren't involved with clotting, why not just try and isolate them anyway. Run a gel, or better, do an immunoassay using a suitable antigen to measure outcome.
I suppose you could decant the plasma out of the anti-coagulant tubes into plain tubes. If you pool the samples you may increase the concentration sufficient to overcome the inhibition by residual anti-coag. Run a gel and look for expression of clotting proteins.