Your blood is a delicate mixture. Researchers and clinicians often use blood to learn what’s going on inside our bodies, in part because siphoning off a tube of blood is easier and less painful than taking biopsies of an internal organ.
But in some cases, it turns out that blood can be very different outside our bodies. When it comes to certain emerging research techniques, the clock starts ticking as soon as your blood hits the tube. As little as six to eight hours later, some aspects of your blood’s molecular composition will have changed to the point that an experiment would give completely different results.
