Certain protocols call for serum to be spun twice, sometimes the second time is at a higher rate.
Can anyone give me a technical explanation for:
1) Why a second time?
2) Why at a higher rate?
I understand why this is carried out with plasma as this is the difference between a platelet rich and platelet poor sample, but as coagulation has already occurred in the serum sample I don't understand why it would be needed.
Unless it's literally being carried out a higher rate to remove any excess erythrocytes?
Even if someone has some references to explain why, it would be great..
It could be to guard against cells remaining in the serum which might contain the analyte you are looking for, giving you a falsely high result.
I think you're correct Emmanuel, its to remove any cellular debris, and ensure purer measurements of extracellular components. I think
In response to your first question Gayle, section 3.1.1.2:
https://books.google.ie/books?id=RU6nndKf7EwC&pg=PA46&lpg=PA46&dq=serum+second+spin&source=bl&ots=k6aOiq9sRw&sig=ACfU3U0oCHVAgveI_xoRkDQuiemR01XsXA&hl=en&sa=X&ved=2ahUKEwiu5bGfpdrgAhUDQhUIHcsxBKwQ6AEwDHoECAkQAQ#v=onepage&q=serum%20second%20spin&f=false
In response to your second comment Gayle:
Yes I think that's a good point in may be to focus more to ensure you're focused on the extracellular environment and no cellular contamination.