Marierose: Though the difference between serum and plasma is that the former lacks fibrinogen, during the coagulation of which however, other plasma proteins might also be part of the clot. Due to the larger amounts of fibrinogen, albumin, etc., there are people who removed a dozen of these abundant proteins prior to "metabolomic" analysis. Some vendors even sell columns to remove these proteins. It is my personal opinion that one needs to use intact plasma to do true metabolomic analysis, as proteins like albumin can bind tens perhaps hundreds of other plasma proteins in the circulation. Hope it helps and good luck.

I prefer plasma, but both are excelente matrices.

Best regards

Gustavo

Evren Caglar Eroglu

We have used both plasma and serum for metabolomics. They both work very well. I usually prefer plasma (K+EDTA) because you can process the samples quickly as with serum you have to let the blood clot before centrifugation. This time can cause some degradation of small molecules. However, a serum separator tube does not have any additives so you are not adding a small molecule to the sample.

For plasma, you should avoid citrated plasma as you will not be able to measure citrate with this. We prefer K+EDTA for plasma.

For all collection, the time to spin down should be kept as constant as possible for all samples and if possible the tubes should be wrapped in Al foil to prevent any light degradation.

Hi, This is a very interesting and relevant question for the entire research community working in metabolomics. Please feel free to register (for free to create a login with your Email ID!) and join the International Metabolomics Society’s Forum: http://www.metabolomics-forum.com/index.php?action=forum;?action=forum#c12 to ask more specific questions any software, database, approach and platform (mass spectrometry, NMR) issues where you can get very specific responses from expert users and researchers! Thanks again, Biswa