Whose** is the answer I guess
The medical term that refers to a blood study that gives a direct measurement of the amount of thyroxin in the patients blood is the THYROXIN LEVEL
Sorry babe i don't get your question if your question is "how does the body use food" then your answer is this (when you eat, your body breaks down all of the starches, sugars, fats, etc. from food that you eat, and uses that from the food you just ate for ENERGY so you can stay alive) so long story short your body uses food for ENERGY....but if that wasn't your question then i'm sorry i don't know