Allergy test? LMFAO! Sounds like you are giving away money to a quack. How about save $ and holiday somewhere sunny over shitty UK winter.
blood sugar, blood pressure, b12 and D levels can change hourly/weekly so repeat tests should be done over months to confirm really. Most big name pro athletes do blood testing daily/weekly.
You are getting ripped off with your supps if consistently your blood values are showing low.
Some people say Freelee is so taught and lean cos of b12 injections she does but sure they help but thats not the main reason haha.
I was super allergic to many fruits and bananas included all of my life, but when I blend them with other fruits no issues at all, or when they are cooked no issues either. I learned this later in life but originally when I ate a raw banana my mouth and gums would itch and my throat would slightly get tight or swell.