Reference intervals for plasma vitamin B12 and plasma/serum methylmalonic acid in Danish children, adults and elderly

Abstract Background Vitamin B12 deficiency in children may be associated with (severe) neurological manifestations, therefore recognition is important. Diagnosing vitamin B12 deficiency in children is challenging. This study aimed to investigate plasma methylmalonic acid, holotranscobalamin, and total cobalamin in children 0–18 years of age and to estimate age-dependent reference intervals. Methods Plasma vitamin B12 markers were measured in collected plasma samples of 170 children 0–18 years visiting a local primary care laboratory. All had within-reference hemoglobin and MCV values. Pediatric plasma vitamin B12 biomarkers were measured and reference values were derived thereof. Results Plasma methylmalonic acid was higher in young children, in particular between 1 and 6 months of age; total cobalamin and holotranscobalamin were highest from 0.5 to 4 years and decreased till 10 years of age. Plasma holotranscobalamin was highly correlated with plasma total cobalamin; their ratio was independent of age. Plasma methylmalonic acid was slightly more related to total cobalamin than to holotranscobalamin. A large proportion of mainly young children would be misclassified when adult references are applied. Conclusions Pediatric reference values for cobalamin markers are necessary to allow for early recognition and monitoring of children suspect of (clinical) cobalamin deficiency. Impact We analyzed three plasma vitamin B12 status markers, i.e., total cobalamin, holotranscobalamin, and methylmalonic acid, in the plasma of 170 children 0–18 years of age and were able to derive reference intervals thereof. Recognition of vitamin B12 deficiency in children is important but challenging as pediatric reference intervals for plasma vitamin B12 status markers, particularly plasma holotranscobalamin, are not well described. We think that our results may help early recognition and monitoring of children suspect of (clinical) vitamin B12 deficiency.

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Measurement of Total Vitamin B12 and Holotranscobalamin, Singly and in Combination, in Screening for Metabolic Vitamin B12 Deficiency

Clinical Chemistry ◽

10.1373/clinchem.2005.061382 ◽

2006 ◽

Vol 52 (2) ◽

pp. 278-285 ◽

Cited By ~ 93

Author(s):

Joshua W Miller ◽

Marjorie G Garrod ◽

Alan L Rockwood ◽

Mark M Kushnir ◽

Lindsay H Allen ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Vitamin B12 ◽

Methylmalonic Acid ◽

Vitamin B12 Deficiency ◽

Reference Intervals ◽

Plasma Vitamin ◽

Roc Curve Analysis ◽

Total Vitamin ◽

B12 Deficiency ◽

Elderly Cohort

Abstract Background: The standard screening test for vitamin B12 deficiency, measurement of total plasma vitamin B12, has limitations of sensitivity and specificity. Plasma vitamin B12 bound to transcobalamin (holoTC) is the fraction of total vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of vitamin B12 status. Methods: We compared the diagnostic accuracy of total vitamin B12, holoTC, and a combination of both measures to screen for metabolic vitamin B12 deficiency in an elderly cohort (age ≥60 years). Plasma methylmalonic acid and homocysteine were used as indicators of vitamin B12 deficiency. Results: Low total vitamin B12 (<148 pmol/L) and low holoTC (<35 pmol/L) were observed in 6.5% and 8.0%, and increased methylmalonic acid (>350 nmol/L) and homocysteine (>13 μmol/L) were observed in 12.1% and 17.0% of the study participants. In multiple regression models, holoTC explained 5%–6% more of the observed variance in methylmalonic acid and homocysteine than did total vitamin B12 (P ≤0.004). ROC curve analysis indicated that total vitamin B12 and holoTC were essentially equivalent in their ability to discriminate persons with and without vitamin B12 deficiency. Individuals with low concentrations of both total vitamin B12 and holoTC had significantly higher concentrations of methylmalonic acid and homocysteine than did individuals with total vitamin B12 and/or holoTC within the reference intervals (P <0.001). Conclusions: HoloTC and total vitamin B12 have equal diagnostic accuracy in screening for metabolic vitamin B12 deficiency. Measurement of both holoTC and total vitamin B12 provides a better screen for vitamin B12 deficiency than either assay alone.

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Diagnostic Performances of Urinary Methylmalonic Acid/Creatinine Ratio in Vitamin B12 Deficiency

Journal of Clinical Medicine ◽

10.3390/jcm9082335 ◽

2020 ◽

Vol 9 (8) ◽

pp. 2335 ◽

Cited By ~ 2

Author(s):

Sopak Supakul ◽

Floris Chabrun ◽

Steve Genebrier ◽

Maximilien N’Guyen ◽

Guillaume Valarche ◽

...

Keyword(s):

Renal Impairment ◽

Vitamin B12 ◽

Methylmalonic Acid ◽

Vitamin B12 Deficiency ◽

Plasma Homocysteine ◽

Plasma Vitamin ◽

Creatinine Ratio ◽

Normal Range ◽

B12 Deficiency ◽

High Degree

Sole measurement of plasma vitamin B12 is no longer enough to identify vitamin B12 (B12) deficiency. When plasma vitamin B12 is in the low-normal range, especially between 201 and 350 ng/L, B12 deficiency should be assessed by measurements of plasma homocysteine and/or plasma methylmalonic acid (MMA). However, these biomarkers also accumulate during renal impairment, leading to a decreased specificity for B12 deficiency. In such cases, urinary methylmalonic acid/creatinine ratio (uMMA/C) could be of interest, due to the stable urinary excretion of MMA. The objectives were to evaluate the influence of renal impairment on uMMA/C compared to plasma homocysteine and plasma methylmalonic acid, and to determine the diagnostic performances of uMMA/C in the diagnosis of B12 deficiency. We prospectively studied 127 patients with a plasma B12 between 201 and 350 ng/L. We noticed that uMMA/C was not dependent on renal function (p = 0.34), contrary to plasma homocysteine and plasma methylmalonic acid. uMMA/C showed a perspective diagnostic performance (AUC 0.71 [95% CI: 0.62–0.80]) and the threshold of 1.45 umol/mmol presented a high degree of specificity (87.9% [95% CI: 72.0–98.9]). In conclusion, uMMA/C is a promising biomarker to assess vitamin B12 status in doubtful cases, notably during renal impairment.

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Relationships between plasma methylmalonic acid and ruminal succinate in cobalt-deficient and -repleted sheep

Australian Journal of Agricultural Research ◽

10.1071/ar05125 ◽

2007 ◽

Vol 58 (4) ◽

pp. 367 ◽

Cited By ~ 1

Author(s):

S. C. Wiese ◽

C. L. White ◽

I. H. Williams ◽

J. G. Allen

Keyword(s):

Vitamin B12 ◽

Methylmalonic Acid ◽

Plasma Concentrations ◽

Plasma Vitamin ◽

Normal Range ◽

Deficient Diet ◽

Wool Growth ◽

Cobalt Deficiency ◽

Vitamin B12 Supplementation ◽

Effective Degree

We measured methylmalonic acid (MMA) in plasma and succinate in the rumen during the depletion of sheep to a state of severe cobalt deficiency and repletion by various forms of supplementation. Groups of 10, cobalt-deficient weaners were allocated to one of 4 treatments: no supplement, 0.1 or 4.0 mg/day of cobalt as a solution of CoSO4.7H2O per os, or intramuscular vitamin B12. Plasma concentrations of MMA were elevated above the normal range (5 µmol/L) after 35 days on the cobalt-deficient diet, before a reduction in feed intake and while liveweights were still increasing. In all 3 supplemented groups of sheep, plasma vitamin B12 concentrations increased to normal levels within 10 days of supplementation (P < 0.001). Plasma MMA concentrations were reduced to normal levels within 10 days with vitamin B12 supplementation but took 31 days with oral cobalt supplementation (P < 0.001). Plasma MMA concentration in the unsupplemented group continued to rise and remain high for the duration of the experiment and did not show the peak and decline to levels indistinguishable from cobalt adequate levels as observed by others. Rumen succinate concentrations were elevated within 6 days of sheep being introduced to a cobalt-deficient diet and in the unsupplemented sheep remained elevated for the duration of measurement. This rise in rumen succinate was seen at a wider range of cobalt intakes than previously reported. In both oral cobalt treatments, vitamin B12 concentrations increased (P < 0.001) and succinate concentrations decreased (P < 0.001) in the rumen to normal levels within 6 days of supplementation. However, the vitamin B12 provided to the sheep by injection was not recycled to the rumen to any effective degree, as demonstrated by the persistence of high rumen succinate concentrations. The ability of the vitamin B12-supplemented sheep to maintain higher rates of wool growth than deficient sheep, while still exhibiting elevated succinate concentrations in the rumen, demonstrates that overcoming the blockage of the methylmalonyl CoA mutase pathway in the rumen is not essential for restoring metabolic pathways such as those responsible for wool growth. This work contributes to the knowledge of plasma MMA and rumen succinate as useful indicators of functional cobalt status and cobalt intake in sheep.

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Reference intervals for serum total vitamin B12 and holotranscobalamin concentrations and their change points with methylmalonic acid concentration to assess vitamin B12 status during early and mid-pregnancy

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2018-1337 ◽

2019 ◽

Vol 57 (11) ◽

pp. 1790-1798 ◽

Cited By ~ 1

Author(s):

Theresa H. Schroder ◽

Amy Tan ◽

Andre Mattman ◽

Graham Sinclair ◽

Susan I. Barr ◽

...

Keyword(s):

Vitamin B12 ◽

Pregnant Women ◽

Change Point ◽

Methylmalonic Acid ◽

Reference Interval ◽

Reference Intervals ◽

Change Points ◽

Change Point Analysis ◽

Future Research ◽

Linear Relationships

Abstract Background Maternal vitamin B12 (B-12) adequacy is important for maternal health and optimal fetal growth. However, pregnancy-specific cut-offs for B-12 biomarkers are lacking. Methods Reference intervals for serum total B-12, holotranscobalamin (holoTC) and methylmalonic acid (MMA) concentrations were calculated following CLSI EP28-A3c guidelines in 723 pregnant women of European (50%) and South Asian (50%) ethnicity, residing in British Columbia, Canada, at median (range) 11.4 (8.3–13.9) and 16.1 (14.9–20.9) weeks of gestation. Change point analyses described relationships between log serum MMA concentration with serum total B-12 and holoTC concentrations, assuming linear-linear relationships. Results The central 95% reference interval limits indicated that serum total B-12 <89.9 and <84.0 pmol/L, holoTC <29.5 and <26.0 pmol/L and MMA >371 and >374 nmol/L, in the first and second trimesters, respectively, may indicate B-12 deficiency in pregnant women. The lower limits of total B-12 and holoTC and the upper limits of MMA significantly differed by ethnicity in both trimesters. According to the change point analysis, total B-12 <186 and <180 pmol/L and holoTC <62.2 and <67.5 pmol/L in the first and second trimesters, respectively, suggested an increased probability of impaired intracellular B-12 status, with no difference between ethnicities. Conclusions We present novel reference limits and change points for B-12 biomarkers, which may be employed to identify possible B-12 deficiency in women during early and mid-pregnancy. Future research is needed to validate these cut-offs and determine the predictors and functional outcomes associated with impaired B-12 status in ethnically diverse populations.

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Determinants of Plasma Methylmalonic Acid in a Large Population: Implications for Assessment of Vitamin B12 Status

Clinical Chemistry ◽

10.1373/clinchem.2009.128678 ◽

2009 ◽

Vol 55 (12) ◽

pp. 2198-2206 ◽

Cited By ~ 78

Author(s):

Anna Vogiatzoglou ◽

Abderrahim Oulhaj ◽

A David Smith ◽

Eha Nurk ◽

Christian A Drevon ◽

...

Keyword(s):

Vitamin B12 ◽

Methylmalonic Acid ◽

Large Population ◽

Dietary Factors ◽

Plasma Vitamin ◽

Middle Aged ◽

Anthropometric Measures ◽

Upper Limits ◽

Unselected Population ◽

The Difference

Abstract Background: Methylmalonic acid (MMA) in plasma or serum is widely used for assessment of vitamin B12 status. However, data are sparse regarding factors, besides renal function, that may influence MMA concentrations. We searched for important determinants of plasma MMA in the general population. Methods: In 6946 middle-aged (47–49 years) and elderly (71–74 years) individuals from the Hordaland Homocysteine Study in Norway, we collected anthropometric measurements, lifestyle data, and plasma MMA, vitamin B12, and creatinine measurements. For 5820 individuals, we also collected dietary data. Results: Age and plasma creatinine were positively associated with plasma MMA, whereas plasma vitamin B12 was negatively associated. These variables together with sex were the strongest determinants of plasma MMA, accounting for 16% of the variation (R2 = 0.16). Addition of anthropometric measures and lifestyle and dietary factors only gave slight improvement (total R2 = 0.167). Increased plasma MMA was seen when plasma vitamin B12 was <400 pmol/L. In individuals with vitamin B12 ≥400 μmol/L (vitamin B12–replete), the 2.5th–97.5th percentile reference limits for MMA were 0.10–0.28 μmol/L (middle-aged) and 0.10–0.36 μmol/L (elderly). When plotted against creatinine (nomograms), the 97.5th percentile of MMA was similar in men and women but approximately 0.15 μmol/L higher in elderly than middle-aged individuals. Vitamin B12–replete participants had MMA upper limits approximately 0.1 μmol/L (elderly) and 0.04 μmol/L (middle-aged) below those of the unselected population at all creatinine concentrations. Conclusions: Identified determinants accounted for <17% of the overall variation in plasma MMA. The difference in MMA between middle-aged and elderly individuals is only partly explained by creatinine and vitamin B12 concentrations.

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The Cobalamin-Binding Proteins Transcobalamin and Haptocorrin in Maternal and Cord Blood Sera at Birth

Clinical Chemistry ◽

10.1373/clinchem.2005.057810 ◽

2006 ◽

Vol 52 (2) ◽

pp. 263-269 ◽

Cited By ~ 37

Author(s):

Rima Obeid ◽

Anne L Morkbak ◽

Winfried Munz ◽

Ebba Nexo ◽

Wolfgang Herrmann

Keyword(s):

Vitamin B12 ◽

Cord Blood ◽

Methylmalonic Acid ◽

Close Correlation ◽

Maternal Blood ◽

Maternal Serum ◽

Total Serum ◽

Plasma Vitamin ◽

Blood Samples ◽

The Relationship

Abstract Background: Two proteins carry vitamin B12 in plasma. Transcobalamin (TC) carries ∼25% of total plasma vitamin B12 and is 6% to 20% saturated with cobalamin. Haptocorrin (HC) binds ∼80% of total cobalamin and is largely saturated with cobalamin. Methods: We investigated the distribution and the relationship between concentrations of cobalamin, total and holo forms of TC, and HC in blood samples from pregnant women just before delivery (n = 92) and in cord blood samples from their newborn babies. We also investigated the relationship between these proteins and concentrations of methylmalonic acid (MMA), the functional marker of vitamin B12 status. Results: Concentrations of total serum cobalamin, total HC, holoHC, and percentage of HC saturation were higher in cord blood than in the maternal blood (mean cobalamin, 268 vs 188 pmol/L; total HC, 648 vs 538 pmol/L; holoHC, 441 vs 237 pmol/L; HC saturation, 70% vs 47%). Moreover, total TC was low in cord blood, whereas both holoTC and TC saturation were higher in cord blood than in the maternal blood (mean total TC, 654 vs 1002 pmol/L; holoTC, 118 vs 53 pmol/L; TC saturation, 19.8% vs 5.4%). Higher maternal serum cobalamin was associated with higher cord blood holoTC and TC saturation (P <0.05). Gestational age was also a significant determinant of baby total TC, TC saturation, total HC, and holoHC. Conclusion: The close correlation between the amounts of holoTC present in cord blood and in maternal serum supports the importance of maternal cobalamin status for ensuring a sufficient supply to the baby.

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Plasma and Red Cell Reference Intervals of 5-Methyltetrahydrofolate of Healthy Adults in Whom Biochemical Functional Deficiencies of Folate and Vitamin B12Had Been Excluded

Advances in Hematology ◽

10.1155/2014/465623 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 9

Author(s):

Agata Sobczyńska-Malefora ◽

Dominic J. Harrington ◽

Kieran Voong ◽

Martin J. Shearer

Keyword(s):

Methylmalonic Acid ◽

Reference Intervals ◽

Healthy Adults ◽

Molecular Forms ◽

Vitamin B ◽

Red Cell ◽

Relationship Of ◽

The Relationship ◽

Plasma Measurements ◽

Functional Deficiency

5-Methyltetrahydrofolate (5-MTHF) is the predominant form of folate and a strong determinant of homocysteine concentrations. There is evidence that suboptimal 5-MTHF availability is a risk factor for cardiovascular disease independent of homocysteine. The analysis of folates remains challenging and is almost exclusively limited to the reporting of “total” folate rather than individual molecular forms. The purpose of this study was to establish the reference intervals of 5-MTHF in plasma and red cells of healthy adults who had been prescreened to exclude biochemical evidence of functional deficiency of folate and/or vitamin B12. Functional folate and vitamin B12status was assessed by respective plasma measurements of homocysteine and methylmalonic acid in 144 healthy volunteers, aged 19–64 years. After the exclusion of 10 individuals, values for 134 subjects were used to establish the upper reference limits for homocysteine (13 μmol/L females and 15 μmol/L males) and methylmalonic acid (430 nmol/L). Subjects with values below these cutoffs were designated as folate and vitamin B12replete and their plasma and red cell 5-MTHF reference intervals determined,N=126: 6.6–39.9 nmol/L and 223–1041 nmol/L, respectively. The application of these intervals will assist in the evaluation of folate status and facilitate studies to evaluate the relationship of 5-MTHF to disease.

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Plasma Vitamin B12 Levels, High-Dose Vitamin B12 Treatment, and Risk of Dementia

Journal of Alzheimer s Disease ◽

10.3233/jad-201096 ◽

2021 ◽

Vol 79 (4) ◽

pp. 1601-1612

Author(s):

Johan Frederik Håkonsen Arendt ◽

Erzsébet Horváth-Puhó ◽

Henrik Toft Sørensen ◽

Ebba Nexø ◽

Lars Pedersen ◽

...

Keyword(s):

Vitamin B12 ◽

Vascular Dementia ◽

Cox Regression ◽

Population Based ◽

High Dose ◽

Plasma Vitamin ◽

Hazard Ratios ◽

B12 Deficiency ◽

First Time

Background: It is controversial whether B12 deficiency causes dementia or B12 treatment can prevent dementia. Objective: To assess associations between low plasma (P-)B12 levels, B12 treatment, and risk of Alzheimer’s disease (AD; primary outcome) and all-cause or vascular dementia (secondary outcomes). Methods: We conducted a population-based cohort study using Danish registry data to assess associations between low P-B12 levels, high-dose injection or oral B12 treatment, and risk of dementia (study period 2000–2013). The primary P-B12 cohort included patients with a first-time P-B12 measurement whose subsequent B12 treatment was recorded. The secondary B12 treatment cohort included patients with a first-time B12 prescription and P-B12 measurement within one year before this prescription. For both cohorts, patients with low P-B12 levels (<200 pmol/L) were propensity score-matched 1:1 with patients with normal levels (200–600 pmol/L). We used multivariable Cox regression to compute 0–15-year hazard ratios for dementia. Results: For low P-B12 and normal P-B12 level groups, we included 53,089 patients in the primary P-B12 cohort and 13,656 patients in the secondary B12 treatment cohort. In the P-B12 cohort, hazard ratios for AD centered around one, regardless of follow-up period or treatment during follow-up. In the B12 treatment cohort, risk of AD was unaffected by low pre-treatment P-B12 levels, follow-up period and type of B12 treatment. Findings were similar for all-cause and vascular dementia. Conclusion: We found no associatio1n between low P-B12 levels and dementia. Associations were unaffected by B12 treatment. Results do not support routine screening for B12 deficiency in patients with suspected dementia.

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The Carriers of Native Vitamin B12 in Normal Human Serum

Clinical Science ◽

10.1042/cs0530453 ◽

1977 ◽

Vol 53 (5) ◽

pp. 453-457 ◽

Cited By ~ 1

Author(s):

C. A. Hall

Keyword(s):

Vitamin B12 ◽

Human Serum ◽

Isotope Dilution ◽

Serum Vitamin ◽

Total Serum ◽

Plasma Vitamin ◽

Isotope Dilution Assay ◽

Dilution Assay ◽

Normal Human ◽

Transcobalamin Ii

1. After fractionation of the vitamin B12-binding proteins of ten normal sera the components containing transcobalamin II and R-type binders of vitamin B12 respectively were studied for endogenous vitamin B12 content by two distinct systems of vitamin B12 assay. 2. The measurements of total serum vitamin B12 by either bioassay with Euglena gracilis or a radioisotope dilution assay agreed closely. 3. The native vitamin B12 carried by transcobalamin II was higher as measured by bioassay than by isotope dilution assay. 4. The presence of the transcobalamin II fraction of human serum altered the key reaction between the binding reagent of the isotope dilution assay, so that this assay failed to measure vitamin B12 quantitatively. 5. Probably, the mean fraction of plasma vitamin B12 carried by transcobalamin II is in the range 20–30%.

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