Issues of methodology, standardization and metabolite recognition for                25-hydroxyvitamin D when comparing the DiaSorin radioimmunoassay and the Nichols                Advantage automated chemiluminescence protein-binding assay in hip fracture                cases

Glendenning, Paul; Noble, Jane M; Taranto, Mario; Musk, Alexander A.; McGuiness, Marjory; Goldswain, Peter; Fraser, William D.; Vasikaran, Samuel

doi:10.1258/000456303322326470

Cited by 61 publications

(33 citation statements)

References 16 publications

(13 reference statements)

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“…The replacement of the traditional RIA with nonisotopically labeled assays has allowed automation of the analysis; however, recent studies have suggested that both the Nichols Advantage automated chemiluminescence protein-binding assay and, to a lesser extent, the IDS RIA underrecover 25-OH D 2 compared with HPLC analysis (22,23 ). Recent publications have highlighted the interlaboratory variability of 25-OH D analysis on patient samples measured by RIA and chemiluminescence assays (24 ) and quality assurance material (22 ).…”

Section: Discussionmentioning

confidence: 99%

Routine Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry Assay for Simultaneous Measurement of the 25-Hydroxy Metabolites of Vitamins D2 and D3

Maunsell¹,

Wright²,

Rainbow³

2005

Clinical Chemistry

348

267

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Section: Discussionmentioning

confidence: 99%

Routine Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry Assay for Simultaneous Measurement of the 25-Hydroxy Metabolites of Vitamins D2 and D3

Maunsell¹,

Wright²,

Rainbow³

2005

Clinical Chemistry

348

267

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“…Assay-related underrepresentation of serum 25OHD concentrations in subjects taking vitamin D supplements was considered, and is possible, in view of the recently reported Nichols' Advantage assay's inadequacy in measuring exogenous sources of vitamin D 2 . 41,42 Nevertheless, our screened subjects were not receiving therapeutic doses of vitamin D 2 (>800 IU of vitamin D 2 ) when their serum 25OHD concentration was measured. Two of the 3 studies in pediatric subjects with IBD to report vitamin D status used a serum 25OHD concentration <15 ng/mL as the cutoff value for vitamin D deficiency and could have, as a result, underestimated the prevalence of this condition.…”

Section: Discussionmentioning

confidence: 99%

“…40 Recent studies have found this assay to be inadequate in measuring exogenous sources of vitamin D 2 . 41,42 To further investigate whether possible assay-related underrepresentation of serum 25OHD concentrations contributed (especially in patients who reported taking vitamin D supplements) to the lack of a relationship between serum PTH and 25OHD concentration, we performed the analysis separately for participants who reported taking vitamin D supplements and those who did not, and we still did not find a significant relationship (Spearman's ρ (r) = 0.13, P = .57 in those not taking vitamin D supplements; r = −0.12, P = .26 in those taking such supplements). To account for effects of puberty, we evaluated the relationship between serum PTH and 25OHD concentrations separately in patients ≤18 years and those >18 years, and we still did not find it to be significant (Spearman's ρ (r) = −0.05, P = .64 in patients ≤18 years; r = −0.43, P = .11 in patients >18 years).…”

Section: Relationships Between Serum 25ohd Concentration and Bone Metmentioning

confidence: 99%

Vitamin D Status in Children and Young Adults With Inflammatory Bowel Disease

Pappa¹,

Gordon

Saslowsky³

et al. 2006

Pediatrics

186

144

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OBJECTIVES-Previous studies of vitamin D status in pediatric patients with inflammatory bowel disease have revealed conflicting results. We sought to report (1) the prevalence of vitamin D deficiency (serum 25-hydroxy-vitamin D concentration ≤15 ng/mL) in a large population with inflammatory bowel disease, (2) factors predisposing to this problem, and (3) its relationship to bone health and serum parathyroid hormone concentration.PATIENTS AND METHODS-A total of 130 patients (8-22 years of age) with inflammatory bowel disease, 94 with Crohn disease and 36 with ulcerative colitis, had serum 25-hydroxyvitamin D, intact parathyroid hormone, and lumbar spine bone mineral density (using dual-energy x-ray absorptiometry) measured at Children's Hospital Boston. RESULTS-The prevalence of vitamin D deficiency was 34.6%. Mean serum 25-hydroxyvitamin D concentration was similar in patients with Crohn disease and ulcerative colitis, 52.6% lower among patients with dark skin complexion, 33.4% lower during the winter months (December 22 to March 21), and 31.5% higher among patients who were taking vitamin D supplements. Serum 25-hydroxy-vitamin D concentration was positively correlated with weight and BMI z score, disease duration, and serum albumin concentration and negatively correlated with erythrocyte sedimentation rate. Patients with Crohn disease and upper gastrointestinal tract involvement were more likely to be vitamin D deficient than those without it. Serum 25-hydroxyvitamin concentration was not associated with lumbar spine bone mineral density z score or serum parathyroid hormone concentration.CONCLUSIONS-Vitamin D deficiency is highly prevalent among pediatric patients with inflammatory bowel disease. Factors predisposing to the problem include having a dark-skin complexion, winter season, lack of vitamin D supplementation, early stage of disease, more severe disease, and upper gastrointestinal tract involvement in patients with Crohn disease. The long-term significance of hypovitaminosis D for this population is unknown at present and merits additional study. Copyright © 2006 by the American Academy of PediatricsAddress correspondence to Helen M. Pappa, MD, MPH, Division of Gastroenterology and Nutrition, Children's Hospital Boston, 300 Longwood Ave, Boston, MA 02115. helen.pappa@childrens.harvard.edu. The authors have indicated they have no financial relationships relevant to this article to disclose. NIH Public Access Author ManuscriptPediatrics. Author manuscript; available in PMC 2011 November 1. Available reports on the vitamin D status of adults with CD place the prevalence of 25OHD concentration ≤15 ng/mL between 22% and 70%, depending on the study. 21-31 Serum 25OHD concentration was found to be <10 ng/mL in 8% to 45% of adults with CD. 21,22,24,26 One study reports a negative relationship among disease duration, Crohn Disease Activity Index, ferritin, C-reactive protein, cholesterol, 24 and 25OHD concentration.Other studies report that smoking 21 and small bowel resection 30,32 are also negativel...

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“…This assay underestimated 25-OHD at low levels and overestimated 25-OHD at high levels resulting in a substantial misclassifi cation of patients (5) . A comparison of the Nichols Advantage assay with liquid chromatography tandem mass spectrometry (LC-MS/MS) also revealed problems with assay linearity (6) and individual patient results were highly variable.…”

Section: Markus Herrmannmentioning

confidence: 95%

The measurement of 25-hydroxy vitamin D – an analytical challenge

Herrmann

2012

Clinical Chemistry and Laboratory Medicine (CCLM)

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Over the last decade requests for the measurement of 25-hydroxy vitamin D (25-OHD) have risen exponentially. For example, statistics from the Australian government provides evidence for a 100-fold increase between 2000 and 2010 (1) . This burst of vitamin D requests has several causes including an increased awareness of the medical community and the general population to the high prevalence of vitamin D defi ciency and its relevance for osteoporosis, cardiovascular disease, malignancies, infectious and autoimmune disease. The massively increased demand for 25-OHD testing has important implications for healthcare systems and clinical laboratories. Whereas healthcare systems worldwide face an explosion of costs for 25-OHD testing, laboratories have to adopt methods that can cope with the elevated workload. External quality control programs show that most laboratories use automated immunoassays. Diagnostic manufacturers have identifi ed 25-OHD as a highly profi table and strategic test, which has lead to the commercialization of new automated immunoassays during recent years. However, it has to be acknowledged that 25-OHD is a challenging analyte to accurately measure in human blood (2) . Analytical diffi culties are related to its lipohilic nature, strong affi nity to vitamin D binding protein (VDBP) and association with human serum albumin, as well as the presence of very low to high levels of 25-OH vitamin D 3 (25-OHD 3 ) and/or 25-OH vitamin D 2 (25-OHD 2 ), multiple 25-OHD metabolites (e.g., 24,25-dihydroxy vitamin D 3 ), C3-epimer of 25-OHD 3 and 25-OHD 2 (25-OHD 3 -epi and 25-OHD 2 -epi), and other sources of assay interference, such as heterophilic antibodies. Therefore, 25-OH vitamin D immunoassays are required to detect 25-OHD 2 and 25-OHD 3 in an equimolar fashion and report a total 25-OHD result.Previous automated immunoassay comparison studies have demonstrated signifi cant analytical limitations for some of these assays (2, 3) . External quality assurance programs, such as DEQAS, or the Quality Assurance Program of the Royal Australian College of Pathologists, also show a wide spread of reported results for the same sample, which in some cases vary from defi cient ( < 25 nmol/L) to suffi cient ( > 75 nmol/L). Analytical problems of 25-OHD immunoassays have also been noted by clinicians who often question the laboratory about results that do not correspond to the clinical picture of their patients. The apparent issues of automated immunoassays have resulted in the worldwide withdrawal of the Roche 25-OHD 3 assay in 2010 and to the modifi cation of the assay conditions of several other commercial immunoassays, such as SIEMENS Centaur, Abbott ARCHITECT and DiaSorin LIAISON. Regulatory bodies, such as the FDA have also become aware of analytical issues with some of the recently launched assays. For example, the FDA has imposed certain conditions on some of the recently cleared 510(k) assays, such as limiting the measuring range of the Abbott ARCHITECT assay from 13 ng/mL (32.5 nmol/ < L) to 96 ng/mL (240...

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Issues of methodology, standardization and metabolite recognition for 25-hydroxyvitamin D when comparing the DiaSorin radioimmunoassay and the Nichols Advantage automated chemiluminescence protein-binding assay in hip fracture cases

Abstract: The discordance between 25-OHD values may be due to differences in standardization of each assay relative to HPLC. Our results emphasize the need for assay-specific clinical decision limits.

Cited by 61 publications

References 16 publications

Routine Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry Assay for Simultaneous Measurement of the 25-Hydroxy Metabolites of Vitamins D2 and D3

Routine Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry Assay for Simultaneous Measurement of the 25-Hydroxy Metabolites of Vitamins D2 and D3

Vitamin D Status in Children and Young Adults With Inflammatory Bowel Disease

The measurement of 25-hydroxy vitamin D – an analytical challenge

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