Exosomes can be isolated from Blood by Ultracentrifugation and Size Exclusion Chromatography Methods

Methods

Blood collection and plasma preparation

After giving their informed consent, venous blood of three healthy volunteers was drawn by using a 21-gauge needle (BD vacutainer, San Jose, CA) and with minimal stasis. Blood, except the first four ml, was collected in 1/10 volume of sodium citrate (3.2%, 0.105 M) using a 4.5 ml BD Vacutainer tube (Becton Dickinson, San Jose, CA). Within 10-15 minutes after withdrawal, blood was centrifuged at 2,000xg for 10 min at 200C, without brake. Plasma was carefully collected and centrifuged again at 2,000xg for 10 min, 2O C, without brake, to obtain platelet poor plasma (PPP). PPP was aliquotted in

250 μl portions, snap frozen in liquid N2, and stored at -8O C until used.

Public source patent application WO2010072410A2

Here's a good primer on EV isolation from various biofluids including blood:

Article Standardization of sample collection, isolation and analysis...

There's a variety of methods to isolate EVs from serum/plasma, most of which will capture different populations and different levels of various contaminants. You'll find a bunch of good papers that compare isolation methods for a given biofluid on Pubmed, which makes it easier to pick one that suits your needs.

Good luck,

Dominik