False elevations of vitamin B12 levels due to assay errors in a patient with pernicious anemia

Iltar, Utku; Göçer, Mesut; Kurtoğlu, Erdal

doi:10.5045/br.2019.54.2.149

Cited by 6 publications

(3 citation statements)

References 7 publications

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“…al reported that normal serum cobalamin cannot exclude functional cobalamin deficiency 3 . High titer of anti‐intrinsic factor antibodies can interfere with cobalamin immunoassays, giving a falsely high result, as in our case 4 . Second‐line tests such as homocysteine, methylmalonic acid, and holotranscobalamin are useful in cases with strong clinical suspicion but with normal serum cobalamin.…”

Section: Discussionmentioning

confidence: 77%

“…3 High titer of anti-intrinsic factor antibodies can interfere with cobalamin immunoassays, giving a falsely high result, as in our case. 4 Second-line tests such as homocysteine, methylmalonic acid, and holotranscobalamin are useful in cases with strong clinical suspicion but with normal serum cobalamin. Vitamin B12 deficiency and MDS are difficult to differentiate on bone marrow examination as both have similar morphological dyserythropoietic changes.…”

Section: Discussionmentioning

confidence: 99%

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Falsely “high” serum cobalamin level in subacute combined degeneration of spinal cord secondary to pernicious anemia masquerading as myelodysplastic syndrome

Yong

Yap

Goh

et al. 2022

Neurology & Clinical Neurosc

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A 62-year-old businessman, with an underlying beta thalassemia trait, presented to the hematology clinic for pancytopenia with hemoglobin 5 g/dl (MCV 75.6 fl, MCH 23 pg), platelet 52 × 10 9 /L, and white cell count 2.65 × 10 9 /L. Peripheral blood film showed anisopoikilocytosis with hypersegmented neutrophils. Vitamin B12 levels were high at 1018 nmol/L (135-675). Serum folate, ferritin, thyroid function, and autoimmune screens were unremarkable. Bone marrow aspirate showed a hypercellular marrow with trilineage dysplasia and ringed sideroblasts <15% of erythroblasts, suggestive of myelodysplastic syndrome-multilineage dysplasia (R-IPSS low risk).Subcutaneous erythropoietin stimulating agents were initiated and he required 2 weekly blood transfusions.Six months later, he reported a 2-year history of progressive bilateral lower limb weakness, which culminated in frequent falls and worsening cognition in the last few months. He denied bladder or bowel incontinence.Neurological examination demonstrated weakness over the bilateral upper and lower limbs with MRC grading of power 4 of 5, hyperreflexia over bilateral lower limbs, a sensory level up to T10 and upgoing extensor plantar reflexes. He had decreased proprioception at the toes and decreased vibration up to the ankles. The Romberg sign was positive. A nerve conduction study showed a mild

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Section: Discussionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Falsely “high” serum cobalamin level in subacute combined degeneration of spinal cord secondary to pernicious anemia masquerading as myelodysplastic syndrome

Yong

Yap

Goh

et al. 2022

Neurology & Clinical Neurosc

View full text Add to dashboard Cite

show abstract

“…Since the 1990s, clinical laboratories have opted for high throughput automated competitive binding chemiluminescence assays (CBLA), using purified IF as a reagent, to measure total cobalamin after its release from endogenous binding proteins [103]. Caution should however be observed when interpreting results, since some of these assays could be influenced by the presence of interfering anti-IF antibodies, particularly in patients with PA, thereby providing spuriously elevated serum cobalamin concentrations in otherwise B 12 -deficient patients [104][105][106].…”

Section: Serum B 12 Testmentioning

confidence: 99%

Vitamin B₁₂status in health and disease: a critical review. Diagnosis of deficiency and insufficiency – clinical and laboratory pitfalls

Sobczyńska‐Malefora

Delvin

McCaddon

et al. 2021

Critical Reviews in Clinical Laboratory Sciences

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Vitamin B 12 (cobalamin) is an essential cofactor for two metabolic pathways. It is obtained principally from food of animal origin. Cobalamin becomes bioavailable through a series of steps pertaining to its release from dietary protein, intrinsic factor-mediated absorption, haptocorrin or transcobalamin-mediated transport, cellular uptake, and two enzymatic conversions (via methionine synthase and methylmalonyl-CoA-mutase) into cofactor forms: methylcobalamin and adenosylcobalamin. Vitamin B 12 deficiency can masquerade as a multitude of illnesses, presenting different perspectives from the point of view of the hematologist, neurologist, gastroenterologist, general physician, or dietician. Increased physician vigilance and heightened patient awareness often account for its early presentation, and testing sometimes occurs during a phase of vitamin B 12 insufficiency before the main onset of the disease. The chosen test often depends on its availability rather than on the diagnostic performance and sensitivity to irrelevant factors interfering with vitamin B 12 markers. Although serum B 12 is still the most commonly used and widely available test, diagnostics by holotranscobalamin, serum methylmalonic acid, and plasma homocysteine measurements have grown in the last several years in routine practice. The lack of a robust absorption test, coupled with compromised sensitivity and specificity of other tests (intrinsic factor and gastric parietal cell antibodies), hinders determination of the cause for depleted B 12 status. This can lead to incorrect supplementation regimes and uncertainty regarding later treatment. This review discusses currently available knowledge on vitamin B 12 , informs the reader about the pitfalls of tests for assessing its deficiency, reviews B 12 status in various populations at different disease stages, and provides recommendations for interpretation, treatment, and associated risks. Future directions for diagnostics of B 12 status and health interventions are also discussed.

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The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action

Travica

Ried

Hudson

et al. 2021

Critical Reviews in Food Science and Nutrition

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False elevations of vitamin B12 levels due to assay errors in a patient with pernicious anemia

Cited by 6 publications

References 7 publications

Falsely “high” serum cobalamin level in subacute combined degeneration of spinal cord secondary to pernicious anemia masquerading as myelodysplastic syndrome

Falsely “high” serum cobalamin level in subacute combined degeneration of spinal cord secondary to pernicious anemia masquerading as myelodysplastic syndrome

Vitamin B₁₂status in health and disease: a critical review. Diagnosis of deficiency and insufficiency – clinical and laboratory pitfalls

The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action

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False elevations of vitamin B12 levels due to assay errors in a patient with pernicious anemia

Cited by 6 publications

References 7 publications

Falsely “high” serum cobalamin level in subacute combined degeneration of spinal cord secondary to pernicious anemia masquerading as myelodysplastic syndrome

Falsely “high” serum cobalamin level in subacute combined degeneration of spinal cord secondary to pernicious anemia masquerading as myelodysplastic syndrome

Vitamin B12status in health and disease: a critical review. Diagnosis of deficiency and insufficiency – clinical and laboratory pitfalls

The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action

Contact Info

Product

Resources

About

Vitamin B₁₂status in health and disease: a critical review. Diagnosis of deficiency and insufficiency – clinical and laboratory pitfalls