Extracellular micronutrients do not aid in body functions. Instead, these nutrients float in the blood outside of the cells. Measuring extracellular micronutrient levels provides a view of your short-term diet over the last few days.
Intracellular micronutrients exist in the white and red blood cells. The micronutrients absorb into the cell and aid in cellular function. Intracellular micronutrient testing reflects your diet over a longer period based on the levels of vitamins and minerals in the cells.