Comparison of Two ELISA Methods and Mass Spectrometry for Measurement of Vitamin D-Binding Protein: Implications for the Assessment of Bioavailable Vitamin D Concentrations Across Genotypes

Denburg, Michelle R.; Hoofnagle, Andrew N.; Sayed, Samir; Gupta, Jayanta; Boer, Ian H. de; Appel, Lawrence J.; Durazo‐Arvizu, Ramón; Whitehead, Krista; Feldman, Harold I.; Leonard, Mary B.

doi:10.1002/jbmr.2829

Cited by 104 publications

(83 citation statements)

References 53 publications

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“…A number of comparison studies have been conducted to evaluate the performance of LC-MS against immunoassays, typically on analytes that give poor and conflicting results in immunoassays such as cortisol [20], glucagon [21] and vitamin D binding protein [22] to name but a few. The studies conducted to date generally show a good correlation between the two methodologies, even if the absolute concentrations differ due to the selectivity differences of both techniques.…”

Section: Comparison Of Immunoassays and Lc-msmentioning

confidence: 99%

Can LC and LC-MS ever replace immunoassays?

Cross¹,

Hornshaw²

2016

J Appl Bioanal

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IntroductionThis review is not intended as a summary of research and development of immunoassays and liquid chromatography-mass spectrometry but rather as a brief summary of the pros and cons of each technology applied to the quantitative measurement of biomolecules primarily in biofluids. The ability to detect and quantitate biomolecules revolutionised science in the twentieth century and continues to this day. It allows scientists, for example, to conduct research to find and validate biomarkers, but has found its most prominent role in diagnostic applications where it is used to monitor the presence and levels of biomolecules in human samples for the diagnosis and monitoring of disease, in food and beverages to ensure food safety and authenticity and in the environment to monitor the presence and levels of contaminants of ground, waste and drinking water. The growth in personalised or precision medicine will be accompanied by an increased need to detect and quantify panels of biomolecules as biomarkers, as well as a range of drugs taken as treatment or as a measure to delay or prevent onset of disease, following the paradigm of the right drug for the right patient at the right time and importantly at the right dose. Increased health and safety regulations demand more testing of food and beverage and environmental samples. With increasing need for biomolecule detection and quantitation comes the demand for high-throughput, lower cost per sample analysis and more accurate results. Traditionally, immunoassays have been the technology of choice for the detection and quantitation of biomolecules. However, over the past two decades alternative technologies have been shown to offer a complementary role to immunoassays. Liquid chromatography-mass spectrometry (LC-MS) is one such technology and for some applications has been shown to offer a powerful alternative to immunoassays. With the increasing demands for routine biomolecule quantitation coming from a broad range of fields, are immunoassays the best solution to keep pace with the increased throughput needed, demand for lower cost per sample and improved accuracy Immunoassays have been the technology of choice for the analysis of biomolecules for many decades across a wide range of applications in research, diagnostics and infectious disease monitoring. There are good reasons for the wide adoption of immunoassays but even such a well established and characterised technique has limitations and as such investigators are looking at alternative technologies. One such alternative is liquid chromatography (LC) and, more specifically, liquid chromatography coupled with mass spectrometry (LC-MS). This article will review both immunoassay and LC and LC-MS technologies and methodologies and discuss the advantages and limitations of both approaches. In addition, the next developments that will need to occur before there is widespread adoption of LC and LC-MS technology preferentially over immunoassays will be examined.

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Section: Comparison Of Immunoassays and Lc-msmentioning

confidence: 99%

Can LC and LC-MS ever replace immunoassays?

Cross¹,

Hornshaw²

2016

J Appl Bioanal

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“…Vitamin D binding protein (VDBP) transports vitamin D metabolites in serum [3]. Up to 90% of vitamin D is bound to VDBP, ~10% binds to albumin and <1% circulates in the free form.…”

Section: Measurement Of Vitamin Dmentioning

confidence: 99%

“…When researchers calculated bioavailable 25(OH)D levels based on VDBP levels, they found that 25(OH)D levels were similar across races. However, a 2016 study [3] concluded that the assay used to measure VDBP in the 2013 study was biased, leading to incorrect conclusions about racial differences in bioactive vitamin D levels.…”

Section: Measurement Of Vitamin Dmentioning

confidence: 99%

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An update on vitamin D for clinicians

Hansen

Johnson

2016

Current Opinion in Endocrinology, Diabetes &Amp; Obesity

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Purpose of review The clinical benefits of vitamin D therapy have received substantial attention over the past decade. Recently, several trials looked to clarify the optimal vitamin D dose or serum level needed to promote human health. The purpose of this review is to highlight selected studies published since January 2015. Recent findings Several recent trials challenge whether serum vitamin D levels ≥30 ng/mL promote human health. In postmenopausal women with 25(OH)D levels 21±3 ng/mL, high-dose vitamin D for one year increased calcium absorption by 1%, without changes in bone mineral density, physical function, or falls when compared to low-dose vitamin D and placebo. High-dose vitamin D increased risk of falling, in 200 adults 78±5 years old with baseline 25(OH)D levels of ~19±9 ng/mL. High-dose vitamin D in adults increased the number and duration of upper respiratory tract infections, compared to placebo. Asthma patients achieving 25(OH)D levels >30 ng/mL during a trial experienced more respiratory infections than those not achieving such levels. Summary Recent studies are congruent with the Institute of Medicine’s conclusion that humans are vitamin D replete when their serum 25(OH)D levels are ≥20 ng/mL. Higher levels seem to promote falls and respiratory infections.

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“…Recently, Powe et al reported that black Americans have lower serum VDBP concentrations as measured by a monoclonal antibody assay than white Americans; therefore, despite a lower total 25-(OH)D level in black Americans, the calculated bioavailable concentration of 25-(OH)D is similar for black and white Americans [5]. These data suggest that the commonly reported low vitamin D levels for black Americans may reflect the measurement of total rather than bioavailable 25-(OH)D concentrations[6]; however, this interpretation remains controversial since results differ with another VDBP assay[7–10]. In addition, two recent studies reported increases in both PTH and VDBP with initiation of tenofovir (TDF)-containing ART [11, 12], suggestive of an induced “functional” vitamin D defiency, but neither study calculated bioavailable 25-(OH)D or compared differences by race.…”

Section: Introductionmentioning

confidence: 99%

Racial differences in calculated bioavailable vitamin D with vitamin D/calcium supplementation

Yin

Chan

Brown

et al. 2017

Aids

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Objectives Some studies suggest that bioavailable 25-(OH)D is more accurate than total 25-(OH)D as an assessment of vitamin D status in black individuals, We hypothesized that increases in bioavailable 25-(OH)D would correlate better with improvement in bone outcomes among black HIV-infected adults. Design This is a secondary analysis of ACTG A5280, a randomized, double-blind study of Vitamin D3 and calcium (VitD/Ca) supplementation in HIV-infected participants initiating antiretroviral therapy (ART). Methods Effect of VitD/Ca on total and calculated bioavailable 25-(OH)D, parathyroid hormone (PTH), bone turnover markers (BTMs) and bone mineral density (BMD) in black and non-black participants were evaluated at 48 weeks. Wilcoxon signed-rank tests and Wilcoxon rank sum tests assessed within and between-race differences. Results Of 165 participants enrolled, 129 (40 black and 89 non-black) had complete data. At baseline, black participants had lower total 25-(OH)D [median (Q1,Q3) 22.6 (15.8, 26.9) vs. 31.1 (23.1, 38.8) ng/ml, p<0.001] but higher bioavailable 25-(OH)D [2.9 (1.5, 5.2) vs. 2.0 (1.5, 3.0) ng/ml, p=0.022] than non-black participants. After 48 weeks of VitD/Ca supplementation, bioavailable 25-(OH)D increased more in black than non-black participants, but there were no between-race differences in change in BTMs or BMD. The associations between increases in 25-(OH)D levels and change in bone outcomes appeared similar for both total and bioavailable 25-(OH)D. Conclusions Baseline and change in bioavailable 25-(OH)D were higher among black adults initiating ART with VitD/Ca; however, associations between 25-(OH)D and bone outcomes appeared similar for total and bioavailable 25-(OH)D. The assessment of total 25-(OH)D may be sufficient for evaluation of vitamin D status in black HIV-infected individuals.

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Comparison of Two ELISA Methods and Mass Spectrometry for Measurement of Vitamin D-Binding Protein: Implications for the Assessment of Bioavailable Vitamin D Concentrations Across Genotypes

Cited by 104 publications

References 53 publications

Can LC and LC-MS ever replace immunoassays?

Can LC and LC-MS ever replace immunoassays?

An update on vitamin D for clinicians

Racial differences in calculated bioavailable vitamin D with vitamin D/calcium supplementation

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