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Clinical Chemistry, Vol 35, 1447-1451, Copyright © 1989 by American Association for Clinical Chemistry
P Gimsing and E Nexo
Department of Internal Medicine and Hematology, Gentofte Hospital, Hillerod, Denmark.
Unsaturated cobalamin-binding capacity in plasma (P-UBBC) is determined by use of a silica gel (QUSO G32) to separate haptocorrin (P-ApoHC) and transcobalamin (P-ApoTC). The method is sensitive and precise: detection limit 13 pmol/L, interassay coefficients of variation 3% for P-UBBC (mean = 1080 pmol/L), 4% for P-ApoTC (mean = 700 pmol/L) (n = 30). Values for P-UBBC, P-ApoHC, P-ApoTC, and P-TBBC (P-UBBC plus P- cobalamin) determined in a population study of 228 individuals, ages 21- 87 years, did not differ by sex. These values increased with age, whereas the cobalamin saturation (P-cobalamin as percentage of P-TBBC) decreased with age. However, these changes were statistically significant but marginal and thus not clinically important. We therefore suggest using combined reference intervals (central 95 percentiles) for all age groups: 500-1200 pmol/L for P-UBBC, 90-275 pmol/L for P-ApoHC, 400-930 pmol/L for P-ApoTC, 850-1600 pmol/L for P- TBBC, and 20-50% for cobalamin saturation. Results for 277 inpatients show high P-ApoHC in myeloproliferative disorders or acute nonlymphatic leukemia, whereas P-ApoTC concentrations are high in some patients with lymphoproliferative disorders or autoimmune diseases.
The following articles in journals at HighWire Press have cited this article:
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R. Obeid, A. L. Morkbak, W. Munz, E. Nexo, and W. Herrmann The Cobalamin-Binding Proteins Transcobalamin and Haptocorrin in Maternal and Cord Blood Sera at Birth Clin. Chem., February 1, 2006; 52(2): 263 - 269. [Abstract] [Full Text] [PDF] |
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Z. Lloyd-Wright, A.-M. Hvas, J. Moller, T. A.B. Sanders, and E. Nexo Holotranscobalamin as an Indicator of Dietary Vitamin B12 Deficiency Clin. Chem., December 1, 2003; 49(12): 2076 - 2078. [Full Text] [PDF] |
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H. Zetterberg, E. Nexo, B. Regland, L. Minthon, R. Boson, M. Palmer, L. Rymo, and K. Blennow The Transcobalamin (TC) Codon 259 Genetic Polymorphism Influences Holo-TC Concentration in Cerebrospinal Fluid from Patients with Alzheimer Disease Clin. Chem., July 1, 2003; 49(7): 1195 - 1198. [Full Text] [PDF] |
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E. Nexo, A.-M. Hvas, O. Bleie, H. Refsum, S. N. Fedosov, S. E. Vollset, J. Schneede, J. E. Nordrehaug, P. M. Ueland, and O. K. Nygard Holo-Transcobalamin Is an Early Marker of Changes in Cobalamin Homeostasis. A Randomized Placebo-controlled Study Clin. Chem., October 1, 2002; 48(10): 1768 - 1771. [Abstract] [Full Text] [PDF] |
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E. Nexo, A.-L. Christensen, T. E. Petersen, and S. N. Fedosov Measurement of Transcobalamin by ELISA Clin. Chem., October 1, 2000; 46(10): 1643 - 1649. [Abstract] [Full Text] [PDF] |
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G. Holleland, J. Schneede, P. M. Ueland, P. K. Lund, H. Refsum, and S. Sandberg Cobalamin Deficiency in General Practice. Assessment of the Diagnostic Utility and Cost-Benefit Analysis of Methylmalonic Acid Determination in Relation to Current Diagnostic Strategies Clin. Chem., February 1, 1999; 45(2): 189 - 198. [Abstract] [Full Text] [PDF] |
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