The rate of blood draw has a direct and measurable effect on the quality of PRF that you produce
With less in circulation, youd expect the effects to be reduced, and a quick search on social media suggests this is probably true, with people asking questions like Why do I feel more hungry on day five to seven?
Regarding plasma B12 - this is not the case, serum B12 often remains highly elevated (well over the normal range) even while symptoms return - this is why testing B12 once treatment begins is not recommended
Jafarirad S, Goodarzi R, Mohammadtaghvaei N, Dastoorpoor M, Alavinejad P
For multi-dose pens, removing visible larger air bubbles helps ensure accurate dosing, though small bubbles are harmless
CagriSemas liver fat data is less extensively reported