SPURIOUS RESULTS FROM DUAL-ISOTOPE (DICOPAC) VITAMIN B12 ABSORPTION TEST ARE DUE TO RAPID OR VARIABLE RATES OF EXCHANGE OF 58Co-B12 FOR 57Co-B12 BOUND TO INTRINSIC FACTOR

1983 ◽  
Vol 4 (1) ◽  
pp. 17-23 ◽  
Author(s):  
V. F. Fairbanks ◽  
H. W. Wahner ◽  
T. B. Valley ◽  
R. M. Scheidt
Keyword(s):  
Vitamin B12 ◽  
Intrinsic Factor ◽  
Absorption Test ◽  
Dual Isotope ◽  
Vitamin B12 Absorption ◽  
Spurious Results

scholarly journals Nonradioactive Vitamin B12 Absorption Test Evaluated in Controls and in Patients with Inherited Malabsorption of Vitamin B12

2005 ◽  
Vol 51 (11) ◽  
pp. 2151-2155 ◽  
Author(s):  
Mustafa Vakur Bor ◽  
Mualla Çetin ◽  
Selin Aytaç ◽  
Çiğdem Altay ◽  
Ebba Nexo
Keyword(s):  
Vitamin B12 ◽  
Intrinsic Factor ◽  
Roc Curves ◽  
Absorption Test ◽  
Factor Deficiency ◽  
Biological Parents ◽  
Passive Absorption ◽  
Vitamin B12 Absorption ◽  
Intrinsic Factor Deficiency ◽  
The Mean

AbstractBackground: Current tests for evaluation of vitamin B12 absorption are problematic because they involve the use of radioactively labeled vitamin B12. We describe a vitamin B12 absorption test that circumvents this problem.Methods: We measured cobalamin or transcobalamin saturated with cobalamin (holo-TC) 24 h after three 9-μg doses of vitamin B12 given orally at 6-h intervals. We studied 17 patients with inherited malabsorption of vitamin B12 attributable to Imerslund–Grasbeck syndrome (n = 13) or intrinsic factor deficiency (n = 4), their obligate heterozygous biological parents (n = 19), and healthy controls (n = 44).Results: In the patients, the median (range) change of holo-TC after the B12 load was not significant [1 (−42 to 5) pmol/L], nor was the change of cobalamin [−3 (−32 to 22) pmol/L], consistent with a lack of measurable active or passive absorption. In controls, however, the median (range) increases of holo-TC and cobalamin were 26 (−6 to 63) pmol/L and 41 (−37 to 109) pmol/L, respectively. Similarly, the parents showed increases of 23 (−2 to 47) pmol/L and 27 (−15 to 94) pmol/L. The mean areas under the ROC curves (95% confidence intervals) were 0.97 (0.93–1.0) for holo-TC and 0.87 (0.79–0.94) for cobalamin, distinguishing patients from controls. At a cutoff of 6 pmol/L for holo-TC, the diagnostic sensitivity (95% confidence interval) was 100 (81–100)%, and the diagnostic specificity was 92 (82–97)%.Conclusion: Measurement of holo-TC after administration of vitamin B12 is a promising approach for evaluating vitamin B12 absorption.

scholarly journals The response to prednisolone in atrophic gastritis: a possible effect on non-intrinsic factor-mediated vitamin B12 absorption

Gut ◽  
1973 ◽  
Vol 14 (1) ◽  
pp. 13-19 ◽  
Author(s):  
R. G. Strickland ◽  
J. M. Fisher ◽  
K. Lewin ◽  
K. B. Taylor
Keyword(s):  
Vitamin B12 ◽  
Atrophic Gastritis ◽  
Intrinsic Factor ◽  
Vitamin B12 Absorption

scholarly journals Vitamin B12 Malabsorption Due to Intrinsic Factor Deficiency in Indian Subjects

Blood ◽  
1972 ◽  
Vol 40 (5) ◽  
pp. 747-753 ◽  
Author(s):  
H. G. Desai ◽  
F. P. Antia
Keyword(s):  
Vitamin B12 ◽  
Pernicious Anemia ◽  
Indian Population ◽  
Intrinsic Factor ◽  
Subacute Combined Degeneration ◽  
Factor Deficiency ◽  
Vitamin B12 Absorption ◽  
Intrinsic Factor Deficiency ◽  
Intrinsic Factor Antibody ◽  
Vitamin B12 Malabsorption

Abstract Sixteen patients (from Bombay) with severe vitamin B12 malabsorption due to intrinsic factor deficiency, presenting as subacute combined degeneration of the cord (7), tropical sprue (3), anemia (2), thyrotoxicosis (2), diabetes mellitus (1), and pain in the abdomen (1), are reported. The difficulties of establishing a definite diagnosis of pernicious anemia in Indian population are described. The lower incidence of circulating intrinsic factor antibody (IFA) in Indian patients with histamine-fast achlorhydria and poor vitamin B12 absorption is emphasized. The necessity of separating atrophic gastritis, with severely impaired vitamm B12 absorption, from pernicious anemia on the basis of absence or presence of IFA in serum and/or gastric juice cannot be overemphasized.

scholarly journals Protein-bound vitamin B12 absorption test.

1988 ◽  
Vol 41 (4) ◽  
pp. 478-479 ◽  
Author(s):  
D W Dawson ◽  
D I Gozzard ◽  
M J Lewis
Keyword(s):  
Vitamin B12 ◽  
Absorption Test ◽  
Vitamin B12 Absorption

Intestinal distribution of intrinsic factor and vitamin B12 absorption

1965 ◽  
Vol 208 (1) ◽  
pp. 14-17 ◽  
Author(s):  
Kunio Okuda ◽  
Katsumi Sasayama
Keyword(s):  
Small Intestine ◽  
Vitamin B12 ◽  
Large Intestine ◽  
Intrinsic Factor ◽  
Vitamin B ◽  
Vitamin B12 Absorption ◽  
Small Intestine Absorption

Evidence is presented that intrinsic-factor (IF) activity is present in the small intestine as far down as the ileal end. Physiologic doses of radioactive vitamin B12 without IF were applied directly into various levels of the intestine by surgical and other means in man and rats, and significant absorption was obtained from the small intestine. Absorption inhibition by ethylenediaminetetraacetate and its counteraction by Ca ion demonstrated that such absorption was dependent on IF action. The large intestine was shown to be incapable of physiologic absorption of vitamin B12, and IF was totally ineffective. It is proposed that physiologically, gastric IF descends with some activity in the small intestine, where more of the food vitamin B12 is liberated by digestion and subjected to IF.

Effect of Rat Intrinsic Factor on Vitamin B12 Absorption in Pernicious Anemia

Science ◽  
1957 ◽  
Vol 126 (3273) ◽  
pp. 558-558 ◽  
Author(s):  
J. ABELS ◽  
M. G. WOLDRING ◽  
J. J. M. VEGTER ◽  
H. O. NIEWEG
Keyword(s):  
Vitamin B12 ◽  
Pernicious Anemia ◽  
Intrinsic Factor ◽  
Vitamin B12 Absorption
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