 By now you would have noticed a trend in how metabolic abnormalities translate into the red cell abnormalities that the automated blood counter picks up. Initially because enough of the cells have not been affected by whatever pathophysiology there is. The first changes to be observed would be a change in variation that is of the sizes of the cells. So like in iron deficiency, in B12 or folate deficiency, there is a nuclear maturation delay that at the beginning is subtle and is only reflective in the size of the cells. Once enough of them have been affected then the other indices would begin to change. So when you see a normal hemoglobin with a normal MCV, that's not the end of the matter. Check to see if the red cell distribution with is within normal. If it is not then you need to observe and anticipate further changes down the line.