title: Problems with vitamin B12 assays.
mesh_terms: D005494:Folic Acid Deficiency / Q000378:metabolism; D006801:Humans; D008314:Malonates / Q000652:urine*; D008764:Methylmalonic Acid / Q000652:urine*; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis*
chemical_list: D008314:Malonates; D008764:Methylmalonic Acid; D014805:Vitamin B 12