caa a22 4500 378852256 CHVBK 20180305123326.0 cr unu---uuuuu 161128e20031117xx s 000 0 eng 10.1515/CCLM.2003.228 doi (NATIONALLICENCE)gruyter-10.1515/CCLM.2003.228 Holotranscobalamin as a Predictor of Vitamin B12 Status [Elektronische Daten] [Anne-Mette Hvas, Ebba Nexo] 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 μmol/l and plasma cobalamins <200 pmol/l, n = 35) and individuals with test results inside the reference intervals (methylmalonic acid <0.29 μmol/l and plasma cobalamins ≥200 pmol/l, n = 35). In a group (n = 37) with low plasma cobalamins (<200 pmol/l) and normal methylmalonic acid (<0.29 μmol/l), 27 individuals had low holotranscobalamin, and in nine of these individuals plasma homocysteine supported the deficiency state (homocysteine >15 μmol/l). Holotranscobalamin was low in 12 individuals with increased methylmalonic acid (>0.40 μmol/l) and normal plasma cobalamins ≥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. Copyright © 2003 by Walter de Gruyter GmbH & Co. KG Medical equipment & techniques nationallicence Medical diagnosis nationallicence Diseases & disorders nationallicence Hvas Anne-Mette aut Nexo Ebba aut Clinical Chemistry and Laboratory Medicine Walter de Gruyter 41/11(2003-11-17), 1489-1492 1434-6621 41:11<1489 2003 41 cclm https://doi.org/10.1515/CCLM.2003.228 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/CCLM.2003.228 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hvas Anne-Mette aut NATIONALLICENCE 700 1- Nexo Ebba aut NATIONALLICENCE 773 0- Clinical Chemistry and Laboratory Medicine Walter de Gruyter 41/11(2003-11-17), 1489-1492 1434-6621 41:11<1489 2003 41 cclm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter