cytokines in serum

txpljfg at txpljfg at
Tue Sep 24 12:33:00 EST 1996

We have routinely collected plasma samples for cytokine analysis in 
vacutainers containing EDTA and aprotinin.  We have found that samples 
should be frozen within an hour (30 minutes if you are measuring TNF.  We 
have done IL-2 measurements in cardiac transplant recipients and found 
very little IL-2 is detectable in the plasma (ditto for IL-2 mRNA as 
well).  Once frozen at -70, the samples are stable for long periods (at 
least months, depending on the cytokine).  It is best if they are 
aliqotted so that freeze/thaw cycles can be avoided.  

On eposting has mentioned that clotted blood is best.  I have never used 
clotted blood, therefore I do not know if clotted blood will give 
equivalent measurements.

Good Luck.

Joan Redd (reddjo at wrote:
> I am beginning a project in which I wish to measure cytokines (IL-2) in human 
> serum, if feasible.  I am new to this area and would appreciate some help on a 
> few questions.

> 1.  How soon after the blood is drawn must it be processed?  Can it be stored 
> in the refrigerator for any length of time, and if so, how long?

> 2.  Can the serum be frozen before it is assayed (ELISA) for the cytokines?

> 3.  What is the optimum procedure for obtaining the serum?  Are there any 
> precautions that must be taken during clotting, etc.?

> Thank you for your assistance.

> Joan Redd
> reddjo at

James F. George, Ph.D.              Transplantation Immunology Laboratory
Department of Surgery               *Please sign your organ donor card* 
University of Alabama at Birmingham
205-934-4261 voice
jgeorge at

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