investigations
Last reviewed 01/2018
Vitamin B6 can be assayed in a number of ways:
- direct measurement of plasma or urinary levels; poor index of activity
- indirectly by measurement of levels of urinary metabolites of tryptophan after a dose of oral tryptophan
- indirectly by assay of in vitro transaminase activity before and after addition of vitamin B6; a rise in activity following the supplement indicates deficiency