How fast do folate (folic acid) levels change? Previous deficient, went from 12 to 8 ug/L in a month, does serum folate (folic acid) fluctuate or have any diurnal variations?

Serum folate (folic acid)... ...levels, to the best of my knowledge, don't have a diurnal variation. However, since we're measuring serum (as opposed to Red Blood Cell) levels, they can increase fairly quickly with either dietary intake of folate (folic acid) rich foods or supplements. They decrease more slowly if you're becoming depleted. Both of these levels are within normal range.