Vit D, B12, ferratin. Normal not enough need optimum.
I have been sick n fatigued for last 6 months. Tested for these today. I got my vit-D, B12 as 33, 350. Hemoglobin n iron also fine. But low ferratin - 7. Learned that for all these vit-d, B12, etc reports only show normal or acceptable levels but you need optimal levels to be at best performance. (V