Maureen has an interesting demonstration at her fingertips.
(Click on the image for larger size. 
Invisible Girl, Heroine: Chapter Three, Page Eleven written and commissioned by Dr. Faustus of EroticMadScience.com and drawn by Lon Ryden is published under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.)
Searching around for an appropriate pendant image, I found this remarkable wineglass, which looks like something a mad scientist might have invented (it was actually sculptor Etienne Meneau.
Image found at .
She would have been smarter with the lancet in a plunger like diabetics use. It gives the same amount of blood, but it retracts the needle, so the pain is almost non existant.
I shall try to remember that, should I ever have to write a scene like this again. As it is, I am drawing on memories of how we did it for homebrew blood-typing back when I was a student. Which was a while back, I must admit.
I realised after I said it that the comment sounded kind of snarky, for which I apologise. Being a Type2 I have donethousands of blood sugar pokes and accidently lost the cap off my plunger. I remember how much it hurt. Again, I apologise for sounding snarky.
FWIW, you didn’t sound snarky to me.