This quality doesn't seem particular to an individual species (I've seen it in both monkey and rat plasma samples). After freezing aliquotted plasma to -70C, it's thawed on ice before pipetted out using a standard Gilson pipette. In some samples, there is a gell like substance that can clog the pipette tip and result in inaccurate pipetting. I've had it happen to maybe 1 in 10 samples. Am I just not thawing the plasma enough? Is there something causing protein coagulation that I can prevent in the aliquot stage?
I also recognized this phenomen with human plasma samples. I am also wondering why this is happening from time to time. We are working with plasma DNA from tumor patients and to protect the circulating tumor DNA we are adding a 0.225ml Neutral buffer formamide to the EDTA blood.... Do you also add some stabilization solution to your blood?
This is easy. Both cryofibrinogen and cryoglobulins will do this. Both occur in various levels in human plasma.
Thawing on ice will cause cryoprecipitation. If you can defrost your samples at 37C, you should be able to avoid this.
Barry Wilbourn's answer is absolutely correct. Thaw your plasma samples as quickly as possible in a 37 - 39C waterbath, but be careful to gently mix the plasma as it thaws and avoid frothing (protein denaturation).
Thanks Rosemary for the extra important information. You should also do this for defrosting foetal calf serum if you use it for tissue culture. Allowing it to just melt on the bench can lead to loss of growth factors in the cryoprecipitate.
I had also faced the similar problem of cryoprecipitation while handling the human plasma samples. Thawing if plasma samples at 37C with regular but gentle mixing overcomes this problem.
If your Assay is not disturbed by Arginine, just add 1.5 mol/l Arginine, pH 8.7 to your samples before freezing/thawing them.
Yes I am agree with Omer Iqbal,Barry Richard,Amit,Rosemary and Kenneth.Solution is 37 degree water bath thawimg.
If plasma is stored for longer periods, high molecular weight proteins may precipitate even when thawed at 37 degrees. Ideally samples should not be stored for more than 2-6 months.
Does anyone have a good publication to read regarding this topic? We use plasma as a coagulase test diagnostic and I am trying to determine if it may affect the accuracy of our results.
Dear I support the idea that it is cryoprecipitate and can be prevented by reduced duration of storage, thawing at 37 degrees centigrade .
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