Do I have to fast before I take a vitamin level blood test?

No! Fasting of?Value. Fasting for most issues not only of low value but often misleading. Ex.: people commonly told to fast before blood glucose test; yet Diabetes Mellitus=elevated blood glucose & glucose most commonly elevated after eating. Thus fasting glucose routinely misses Diabetes Mellitus. Fasting is promoted for only a few issues because how databases were done or because the values are calculated/estimated.
Not usually. Fasting levels are more important for blood sugar levels, cholesterol, triglycerides as eating can affect these levels, and potentially elevate them, and you'll have to repeat it again. Should not affect vitamin levels in general however.

Related Questions

I have been advised that a recent blood test shows my levels of Vitamin D is 8. What does this mean for me?

Serious deficiency. The level that you're at is critically low. You need to start proper supplementation right away. It's also important to take vitamin K2 and vitamin A along with D3. Make sure you have your doctor follow your blood levels until you get to 50 ng/dl. Get more information here . Read more...