Difference between plasma and serum - (Jan/27/2005 )

Hallo, I'd like to ask about probably trivial thing but could somebody explain the difference between plasma and serum? I need to asssay for C-peptide and anti-GAD from the human blood specimens and am looking for any helpful information. Thank you very much.
Paja

serum is the liquid part of blood AFTER coagulation, therfore devoid of clotting factors as fibrinogen. plasma is the liquid, cell-free (by centrifugation, for example) part of blood, that has been treated with anti-coagulants.

mike

To be more simple i can say serum= plasma - fibrinogen.

To get serum, you need to let the blood clotted and after centrifuge. The upper supernatant is the serum without any clotting factors.

to get plasma, you add anticoagulant like heparin in the blood to avoid clotting and then centrifuge. The upper supernatant is the plasma which contain clotting factors (fibrinogen). Because of the anticoagulant these clotting factors cannot work and because of their density, they cannot go to the bottom after centrifugation. That`s why they are mixed in the upper liquid which called plasma.