No idea. I’ve gone back through all my blood work the past few years and don’t see a Vit D analysis. I was insufficient on B12 and take a supplement for that.
You have to ask for it, because it is not a standard test. It should be a standard test, and why it isn’t, with so many people deficient (and everyone told to slather on sunscreen), should be the subject of a Congressional inquiry. In reality you should get that Vit D test before you supplement with the D3.
Check out the Vitamin D Council (by John Cannell MD) for the best info. This info will in all likelihood be different from what your MD tells you.