Serum vitamin B12 and vitamin B12 binding capacity in chronic myelogenous leukemia and other disorders

Studies on Derivation of Transcobalamin III from Granulocytes ENHANCEMENT BY LITHIUM AND ELIMINATION BY FLUORIDE OF IN VITRO INCREMENTS IN VITAMIN B12-BINDING CAPACITY

“…With EDTA-NaF for blood collection, 12 normal adult men showed a UBBC range of 380-921 pg/ml (mean: 640), and 10 normal adult women had a UBBC range of 505-1,208 pg/ml (mean: 809). A higher normal range was found for serum (611-2,036), similar to the ranges of the order of approximately 600-2,200 pg/ml reported previously (4,(22)(23)(24)(25)(26) presumably due to the release of TC III from the cells in vitro after collection in prior studies. The current studies suggest that for uniformity, reproducibility, and similarity to the levels in vivo, samples should be collected in EDTA-47 mM NaF when UBBC levels are desired.…”

Unusual Presentation of Vitamin B12Deficiency

“…Cobalamin deficiency may be present without anemia and macrocytosis and even with normal or elevated serum vitamin B 12 in conditions with (a) increased cobalamin binders in such conditions as polycythemia vera, chronic myelogenous leukemia; (b) increased cobalamin analogues which are indistinguishable from vitamin B 12 by the current radioimmunoassay; and (c) exposure to nitrous oxide which abolishes vitamin B 12 function [25][26][27][28][29].…”

“…Patients with achlorhydria, for instance, commonly present with unresponsive iron deficiency anemia due to masked vitamin B 12 deficiency [3][4][5][6][7][8][9][10][11]. Vitamin B 12 deficiency may present with neuropsychiatric manifestations in the absence of hematological abnormalities [12][13][14][15][16][17][18][19][20][21][22][23][24].Vitamin B 12 deficiency may even present with normal or elevated serum B 12 when associated with myeloproliferative disorders, leukocytosis, exposure to nitrous oxide, or conditions with increased cobalamin binders and/or analogues [25][26][27][28][29].In this paper we report nine cases (Table) with cobalamin deficiency in whom the diagnosis was delayed because of unusual presentation. Vitamin B 12 was measured when cobalamin deficiency was suspected because of unexplained neuropsychiatric symptoms or unresponsive iron deficiency anemia.…”

“…Raised gastric pH (achlorhydria) for any reason may present with combined vitamin B 12 and iron deficiency (due to reduced acidity which is needed for iron absorption and reduced intrinsic factor which is necessary for vitamin B 12 absorption). The cause of achlorhydria was not obvious except in the single case with pernicious anemia [1,2].Although pernicious anemia is not common in this part of the world, vitamin B 12 deficiency due to other causes may not be so uncommon [31].Cobalamin deficiency may be present without anemia and macrocytosis and even with normal or elevated serum vitamin B 12 in conditions with (a) increased cobalamin binders in such conditions as polycythemia vera, chronic myelogenous leukemia; (b) increased cobalamin analogues which are indistinguishable from vitamin B 12 by the current radioimmunoassay; and (c) exposure to nitrous oxide which abolishes vitamin B 12 function [25][26][27][28][29].Vitamin B 12 deficiency should be suspected in conditions with unexplained neuropsychiatric symptoms and signs even in the absence of hematological abnormalities; in such conditions, vitamin B 12 deficiency should be suspected even if serum B 12 levels are normal and ancillary tests need to be performed. These include: (1) leukocyte…”

“…Vitamin B 12 deficiency may even present with normal or elevated serum B 12 when associated with myeloproliferative disorders, leukocytosis, exposure to nitrous oxide, or conditions with increased cobalamin binders and/or analogues [25][26][27][28][29].…”