Besides a plethora of things that can occur[1], the main issue is a combination a pain response and a foreign object entering the skin. When a you stick a need

Besides a plethora of things that can occur[1], the main issue is a combination a pain response and a foreign object entering the skin. When a you stick a needle in a persons arm you often trigger a flight-or-flight repsponse. It's actually fairly similar if you prick their finger. The problem with this study is that one was done after or before the other. It depends what you look for, but for example white blood count (which was tested) would/should change subtly after a blood draw. The amount can vary (or not vary) depending on the person. For example, when I get my blood drawn my arm swells, it's not actually that I am allergic, but my body reacts in said way. Regardless, my only comment was that the study seemed to be on somewhat shaky footing. [1] http://www.frhg.org/documents/Lab_Manuals/Blood-Collection-Adverse-Reactions-and-Patient-Blood-Volumes.pdf http://www.frhg.org/documents/Lab_Manuals/Blood-Collection-A...