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Holotranscobalamin as a predictor of vitamin B12 status.
Clin Chem Lab Med. 2003 Nov; 41(11):1489-92.CC

Abstract

We report on the performance of a new test, holotranscobalamin, as compared to well established markers of vitamin B12 deficiency (plasma cobalamins, methylmalonic acid, and homocysteine). Holotranscobalamin was analyzed in 143 samples by a competitive radiobinding assay (Axis-Shield). Employing a cut-off value of 50 pmol/l, holotranscobalamin showed a sensitivity of 1.00 and a specificity of 0.89 as regards discriminating between individuals with test results indicating vitamin B12 deficiency (methylmalonic acid > 0.70 micromol/l and plasma cobalamins < 200 pmol/l, n = 35) and individuals with test results inside the reference intervals (methylmalonic acid < 0.29 micromol/l and plasma cobalamins > or = 200 pmol/l, n = 35). In a group (n = 37) with low plasma cobalamins (< 200 pmol/l) and normal methylmalonic acid (< 0.29 micromol/l), 27 individuals had low holotranscobalamin, and in nine of these individuals plasma homocysteine supported the deficiency state (homocysteine > 15 micromol/l). Holotranscobalamin was low in 12 individuals with increased methylmalonic acid (> 0.40 micromol/l) and normal plasma cobalamins (> or = 200 pmol/l) (n = 36), and plasma homocysteine supported the deficiency state in four of these individuals. We conclude that holotranscobalamin is likely to be a sensitive marker of vitamin B12 deficiency that also has a reasonable specificity. Large-scale clinical studies are warranted in order to clarify the usefulness of holotranscobalamin in the clinical setting.

Authors+Show Affiliations

Department of Clinical Biochemistry, Aarhus University Hospital, AKH, Aarhus, Denmark.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

14656030

Citation

Hvas, Anne-Mette, and Ebba Nexo. "Holotranscobalamin as a Predictor of Vitamin B12 Status." Clinical Chemistry and Laboratory Medicine, vol. 41, no. 11, 2003, pp. 1489-92.
Hvas AM, Nexo E. Holotranscobalamin as a predictor of vitamin B12 status. Clin Chem Lab Med. 2003;41(11):1489-92.
Hvas, A. M., & Nexo, E. (2003). Holotranscobalamin as a predictor of vitamin B12 status. Clinical Chemistry and Laboratory Medicine, 41(11), 1489-92.
Hvas AM, Nexo E. Holotranscobalamin as a Predictor of Vitamin B12 Status. Clin Chem Lab Med. 2003;41(11):1489-92. PubMed PMID: 14656030.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Holotranscobalamin as a predictor of vitamin B12 status. AU - Hvas,Anne-Mette, AU - Nexo,Ebba, PY - 2003/12/6/pubmed PY - 2004/2/10/medline PY - 2003/12/6/entrez SP - 1489 EP - 92 JF - Clinical chemistry and laboratory medicine JO - Clin Chem Lab Med VL - 41 IS - 11 N2 - We report on the performance of a new test, holotranscobalamin, as compared to well established markers of vitamin B12 deficiency (plasma cobalamins, methylmalonic acid, and homocysteine). Holotranscobalamin was analyzed in 143 samples by a competitive radiobinding assay (Axis-Shield). Employing a cut-off value of 50 pmol/l, holotranscobalamin showed a sensitivity of 1.00 and a specificity of 0.89 as regards discriminating between individuals with test results indicating vitamin B12 deficiency (methylmalonic acid > 0.70 micromol/l and plasma cobalamins < 200 pmol/l, n = 35) and individuals with test results inside the reference intervals (methylmalonic acid < 0.29 micromol/l and plasma cobalamins > or = 200 pmol/l, n = 35). In a group (n = 37) with low plasma cobalamins (< 200 pmol/l) and normal methylmalonic acid (< 0.29 micromol/l), 27 individuals had low holotranscobalamin, and in nine of these individuals plasma homocysteine supported the deficiency state (homocysteine > 15 micromol/l). Holotranscobalamin was low in 12 individuals with increased methylmalonic acid (> 0.40 micromol/l) and normal plasma cobalamins (> or = 200 pmol/l) (n = 36), and plasma homocysteine supported the deficiency state in four of these individuals. We conclude that holotranscobalamin is likely to be a sensitive marker of vitamin B12 deficiency that also has a reasonable specificity. Large-scale clinical studies are warranted in order to clarify the usefulness of holotranscobalamin in the clinical setting. SN - 1434-6621 UR - https://www.unboundmedicine.com/medline/citation/14656030/Holotranscobalamin_as_a_predictor_of_vitamin_B12_status_ DB - PRIME DP - Unbound Medicine ER -