Diagnosis of vitamin B12 deficiency: combined indicator of B12-status should be interpreted with caution in the case of renal impairment.

Keywords: biomarker; renal function; vitamin B12 EN biomarker renal function vitamin B12 e157 e159 3 03/13/21 20210401 NES 210401 To the Editor, The sole measurement of plasma vitamin B12 (B12) is no longer enough to identify vitamin B12 deficiency. Different biomarkers could be used to diagnose B12 deficiency: total plasma homocysteine (tHcy), plasma methylmalonic acid (pMMA), and plasma holotranscobalamin (holoTC) [[1]]. [Extracted from the article]