Talk to Endocrinologist on Vit D

AoA ...agr koi doctor kahy k every normal human body require 21 weekly tablets of Vit D for a year ... without checking deficiency test ...is it true ?? Q k internet aisa guide nai krta wahan info hy k deficiency ajany k bad 6 to 12 weeks depend krta Dr prescribe kry vit D tab lain to ya hardly 12 tablets banty vit D weekly k Kya 21 weekly cap or inj bina test k ly leni chai hain? Kindly doctor's Sahi guide krn thank you