How to obtain serum from blood - (Apr/01/2008 )

Hi everybody!

I am new here...

Can you give me suggestions on how to obtain serum from blood?

I know I have to collect blood in tubes without anticoagulant. But how can I remove the clot then?
Should I centrifuge? How strong? Do I need to use gel containing-tubes or just empty sterile tubes?

In particular I need complement-preserved serum, meaning that I will need to assay complement activity in the serum. Are there particular suggestion that you can give me, if there are experts in the topic?

Thank you very much for your attention,

Alessio

hi there

for separating serum from the blood cells you should use a tube without any anticoagulant , sterile empty tube will be fine , after taking your sample , say 5 ml or so leave the tube in a standing position for about 20-30 minutes ( it can take shorter time than this so you can check it preiodically ) after that you will find your blood to be clotted , centrifuge at 20 c degree , 1500g for 10 minutes then remove your serum very quickly and flash freeze it in -80 c to preserve your complememnt for next assay.

hope this help.

Thank you for your help, spanishflower!

I think I have not waited enough for the clot to form. I was afraid that the complement degrades and so I have spun the blood few minutes after collection.
Next time I will try to wait 20-30 minutes and than spin the clot down.

Cheers

Alessio

We're a clinical lab and we do C3/C4 routinely. We use a gel tube with a clotting accelarator. Centrifugation at 1500g for 10 mins pulls the cells below the gel layer. The serum is then effectively sealed off from the cells. Store at 4degs C. We then use an automated method that uses immunoturbidimetry (TRIS buffer based, goat antibodies). The method is traceable to CRM 470 (Reference Preparation for Proteins in Human Serum). This method advocates serum, samples but has been validated for use on plasma (use Li-heparin tubes).

I work with human serum for my experiments but unlike yours, I do not want complements; so separation of serum is followed by decomplementation.

To collect serum, I draw blood without anti-coag and then put it in a Vacutainer/serum tube for more than 30 mins. Then, I centrifuge the tube at 3000rpm for 5 mins and collect the serum and store at -80 deg.