I know the Vitamin D test is called (D25OH) Vitamin D 25 Hydroxy, I am getting that checked next month. I was low back in april so was put on 800 IU, but told i could stop during the summer months, (i could get vit. d naturally), I have blood work drawn again in about 3 weeks to see how it is and if i should continue with the 800 IU once a day. The other Vitamin I am deficient in is B12 that has given me pernecious anemia, which means my body has stopped making it so need to take it artifically either through injection or a take something i spray in my nose once a week for the rest of my life. So i think it is those that people are asking you about. hope this helps.
Your doctor will know what he name of the test is. They write the request for pathology. You just ask to have your Vit D levels checked. Vit D is normally taken from sunlight and directly acts in your gut to absorb calcium..that's its only function.
If you are thinking you might be low then really the best way is by supplements. Yes, there are some foods which contain fortified Vit D in them like milk or margarine and sometimes cereals. Often these levels are quite low and are for the average person who is not suffering a loss to begin with.
You may want to make sure you have iron studies done too. Often low iron goes hand in hand with low Vit D.
I know all this as I have the condition!
Hope that helps.
Looks like some great answers! Thanks ladies .. C~