Diagnosis of vitamin B12 deficiency.

Dawson, D W

doi:10.1136/bmj.289.6450.938

Cited by 9 publications

(4 citation statements)

References 19 publications

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“…It is important to establish this diagnosis, as these patients can be treated by oral administration of vitamin B 12 1420 26 It should be noted that in certain cases, malabsorption is due to both deficient food vitamin B 12 release and to bacterial overgrowth related to deficient gastric acid secretion 4142 In such cases normal vitamin B 12 absorption can be restored by oral antibiotic therapy 41…”

Section: Discussionmentioning

confidence: 99%

Prospective evaluation of protein bound vitamin B₁₂(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with ⁵⁷Co-cobalamin

Aimone-Gastin

Pierson

Jeandel

et al. 1997

Gut

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Background-The frequency of dietary protein bound vitamin B 12 malabsorption in elderly patients remains controversial. Aims-To evaluate this malabsorption in elderly hospitalised patients using a modified Schilling test. Patients-Fourteen elderly patients with low B 12 blood levels were prospectively selected from 394 hospitalised patients. Methods-The modified Schilling test was performed with trout labelled in vivo.Results-The test was normal in five healthy elderly subjects, in 7/8 patients with pancreatic insuYciency, and in nine non-elderly patients with antral gastritis. The low decision limit was established at 3.3% (median 4.8%). From the 14 elderly patients with low B 12 prospectively selected from 394 hospitalised patients, seven had a real deficiency with anaemia and an increased homocysteine and/or methylmalonate serum level. The modified Schilling test showed malabsorption in five of these patients, including two in which the standard Schilling test was normal, and three in which the standard Schilling test was partially corrected by an intrinsic factor. Conclusions-Protein bound vitamin B 12 malabsorption was detected in at least 0.5% of elderly hospitalised patients, using the labelled trout flesh absorption test. (Gut 1997; 41: 475-479)

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Section: Discussionmentioning

confidence: 99%

Prospective evaluation of protein bound vitamin B₁₂(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with ⁵⁷Co-cobalamin

Aimone-Gastin

Pierson

Jeandel

et al. 1997

Gut

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“…Low serum Cbl values in patients without hematologic abnormalities are frequently encountered in screening studies (16)(17)(18)(19), in the elderly (20,21), and in patients with certain neuropsychiatric abnormalities (22,23), but their significance has been difficult, if not impossible, to determine. More rarely, diagnostic problems can also develop in patients with hematologic abnormalities, since serum Cbl levels may be normal in Cbl-deficient patients who have elevated levels ofCblbinding proteins (24).…”

Section: Introductionmentioning

confidence: 99%

“…At the present time, the serum Cbl assay is essentially the only laboratory test generally available for use in determining if a patient is Cbl-deficient, and this limitation has been widely recognized (16)(17)(18)(19). Low serum Cbl values in patients without hematologic abnormalities are frequently encountered in screening studies (16)(17)(18)(19), in the elderly (20,21), and in patients with certain neuropsychiatric abnormalities (22,23), but their significance has been difficult, if not impossible, to determine.…”

Section: Introductionmentioning

confidence: 99%

Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

Stabler¹,

Marcell²,

Podell³

et al. 1986

J. Clin. Invest.

163

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To determine the incidence of elevated levels of serum methylmalonic acid in patients with cobalamin deficiency, we utilized a new capillary gas chromatographic-mass spectrometric technique to measure methylmalonic acid in the serum of 73 patients with clinically confirmed cobalamin deficiency. Values ranged from 55 to 22,300 ng/ml, and 69 of the 73 patients had values above the normal range of 19-76 ng/ml as determined for 50 normal blood donors. In the cobalamin-deficient patients, serum methylmalonic acid was significantly correlated with the serum folate level and the degree of neurologic involvement. Some patients with pernicious anemia who were intermittently treated with cyanocobalamin were found to have elevated serum levels of methylmalonic acid while free of hematologic and neurologic abnormalities. A cobalamin-deficient patient is described with a normal serum cobalamin and an elevated serum methylmalonic acid. We conclude that the ability to measure methylmalonic acid in human serum will be useful in studies designed to determine the incidence of cobalamin deficiency in various patient populations. IntroductionPrevious investigators have shown that most patients with cobalamin (Cbl, vitamin B12)' deficiency have elevated levels of methylmalonic acid in their urine (1-12). The origin of the methylmalonic acid has recently been elucidated (13) and is illustrated in Fig. 1. In Cbl deficiency, reduced levels ofadenosylCbl result in decreased activity of L-methylmalonyl-coenzyme A (CoA) mutase and a resultant increase in intracellular levels ofL-methylmalonyl-CoA. D-methylmalonyl-CoA is also elevated due to the activity of D,L-methylmalonyl-CoA racemase (14) and is cleaved to coenzyme A and methylmalonic acid by the recently recognized and characterized enzyme, D-methylmalonyl-CoA hydrolase (13). Methylmalonic acid is then released into blood in unknown amounts and is excreted in the urine. In normal individuals (15) and laboratory animals (13), about

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“…The limitations in using only the serum Cbl level to detect Cbl deficiency have been widely recognized (1)(2)(3)(4). For example, the significance of the high incidence of low serum Cbl values in elderly subjects without hematologic abnormalities (5, 6), puscular volume. and in patients who have various neuropsychiatric abnormalities (7,8), is not known.…”

Section: Introductionmentioning

confidence: 99%

Elevation of total homocysteine in the serum of patients with cobalamin or folate deficiency detected by capillary gas chromatography-mass spectrometry.

Stabler

Marcell²,

Podell³

et al. 1988

J. Clin. Invest.

437

173

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To determine if levels of serum total homocysteine are elevated in patients with either cobalamin or folate deficiency, we utilized a new capillary gas chromatographic-mass spectrometric technique to measure total homocysteine in the serum of 78 patients with clinically confirmed cobalamin deficiency and 19 patients with clinically confirmed folate deficiency. Values ranged from 11 to 476 itmol/liter in the cobalamin-deficient patients and 77 of the 78 patients had values above the normal range of 7-22 ;tmol/liter as determined for 50 normal blood donors. In the cobalamin-deficient patients, serum total homocysteine was positively correlated with serum folate, mean corpuscular volume, serum lactate dehydrogenase, serum methylmalonic acid, and the degree of neurologic involvement, and inversely correlated with platelets and hematocrit. In the folate-deficient patients, values for serum total homocysteine ranged from 17 to 185 gmol/liter and 18 of the 19 patients had values above the normal range. Some patients with pernicious anemia who were intermittently treated with cyanocobalamin were found to have elevated serum levels of total homocysteine while they were free of hematologic and neurologic abnormalities. The measurement of serum total homocysteine will help define the incidence of cobalamin deficiency and folate deficiency in various patient populations.

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Diagnosis of vitamin B12 deficiency.

Cited by 9 publications

References 19 publications

Prospective evaluation of protein bound vitamin B₁₂(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with ⁵⁷Co-cobalamin

Prospective evaluation of protein bound vitamin B₁₂(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with ⁵⁷Co-cobalamin

Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

Elevation of total homocysteine in the serum of patients with cobalamin or folate deficiency detected by capillary gas chromatography-mass spectrometry.

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Diagnosis of vitamin B12 deficiency.

Cited by 9 publications

References 19 publications

Prospective evaluation of protein bound vitamin B12(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with 57Co-cobalamin

Prospective evaluation of protein bound vitamin B12(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with 57Co-cobalamin

Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

Elevation of total homocysteine in the serum of patients with cobalamin or folate deficiency detected by capillary gas chromatography-mass spectrometry.

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Prospective evaluation of protein bound vitamin B₁₂(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with ⁵⁷Co-cobalamin

Prospective evaluation of protein bound vitamin B₁₂(cobalamin) malabsorption in the elderly using trout flesh labelled in vivo with ⁵⁷Co-cobalamin