&gt;  Time, skill required and volume are all in favor of the finger prick method. And some people absolutely freak out about needles but would be ok with a finger prick.<p>Except the pain factor. Finger pricks are actually more painful, particularly when you have to draw more than a single drop of blood. Your fingers have more nerve endings than your upper arm. Also, you tend to use your fingers more than you apply pressure to your upper arm (e.g., typing, using your phone, playing the guitar - all of those require applying pressure to your fingertips, which will hurt).<p>Even diabetics oftentimes prefer to use the arm pricks, and they need to draw a lot less blood than more elaborate tests need. (Not all diabetics, but enough that there are literally blood glucose monitors that advertise this as a specific feature).