Question:What to do when different folate markers don’t line up You know, if you have high figlu on the NutrEval, which is Formiminoglutamic acid, which rises when there is Tetrahydrofolate THF, unmethylated folate, to metabolize figlu, and in that case, I would be thinking about maybe you have a B12 deficiency that is leading to the trapping of folate as the methylfolate form, so that THF isn't regenerated for that reaction. So I would absolutely never use figlu as the only marker of folate. I would look at serum folate and red blood cell folate always as the first markers of folate. So in this case, I would look at your serum folate and your red blood cell folate.
So before I would get folate injections, I would be looking at all those markers to see whether there's a coherent story between all of them that are agreeing that your folate status is low despite supplements, versus a divergence story between them that is telling me that one form of folate is the one that's missing rather than a total folate.