title: The limited value of methylmalonic acid, homocysteine and holotranscobalamin in the diagnosis of early B12 deficiency.
abstract: Treatment of B12 deficiency is important to prevent progressive neurological and/or hematologic disease but requires a secure diagnosis. The aim of this study was to evaluate second line tests of B12 status as prognostic indicators of a hematologic response to vitamin B12 therapy. Forty-nine patients referred with low, serum vitamin B12 concentrations were treated with intramuscular B12 and re-assessed after 3 months. Methylmalonic acid, homocysteine, holotranscobalamin and neutrophil hypersegmentation index were measured before and after treatment. Before treatment 27/49 patients were anemic or macrocytic of whom 15 had a clear hematologic response. All the tests had a similar prognostic accuracy. Symptomatic improvement did not correlate with hematologic response. Supplementary tests of vitamin B12 status were not significantly better than total serum B12 concentration as predictors of a hematologic response to vitamin B12 therapy.
authors.affiliation: Department of Haematology, University Hospital of Wales, Cardiff CF14 4XN, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Goringe
authors.forename: Richard
authors.initials: R
authors.lastname: Ellis
authors.forename: Ian
authors.initials: I
authors.lastname: McDowell
authors.forename: Josep
authors.initials: J
authors.lastname: Vidal-Alaball
authors.forename: Christopher
authors.initials: C
authors.lastname: Jenkins
authors.forename: Christopher
authors.initials: C
authors.lastname: Butler
authors.forename: Mark
authors.initials: M
authors.lastname: Worwood
mesh_terms: D003933:Diagnosis; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008764:Methylmalonic Acid / Q000097:blood*; D012680:Sensitivity and Specificity; D014155:Transcobalamins / Q000008:administration & dosage* / Q000032:analysis*; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis*
chemical_list: D014155:Transcobalamins; D006710:Homocysteine; D008764:Methylmalonic Acid