How do I calculate the conversion for Whole Blood Nutrient Profile vitamin D3 to conventional vitamin D, 25-OH?

It is not possible to convert vitamin D3 levels into conventional vitamin D, 25-OH. Vitamin D3 and Vitamin D, 25-OH are different compounds. Therefore, vitamin D3 levels cannot be converted to Vitamin D, 25-OH levels. (2) Whole Blood Nutrients collected via microtube is a mix of capillary blood, arterial blood, interstitial fluid and extracellular fluid. Vitamin D values as measured by microtube collection (instead of venipuncture) cannot be compared, or converted into, to conventional (serum only) values.