Impact of assay design on test performance: lessons learned from 25-hydroxyvitamin D

Farrell, Christopher-John L; Soldo, Joshua; McWhinney, Brett; Bandodkar, Sushil; Herrmann, Markus

doi:10.1515/cclm-2014-0111

Cited by 15 publications

(19 citation statements)

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“…On the other hand, accurate prevalence data on vitamin D levels could be essential for optimizing design and analysis of future clinical trials. As described recently [Heaney et al 2014 [Farrell et al 2014;Glendenning, 2015]. One of these is the ability of the assay to fully rec- [Heijboer et al 2012;Cavalier et al 2014].…”

Section: Achieving Adequate Maternal Vitamin D Levelsmentioning

confidence: 99%

Maternal vitamin D levels during pregnancy and neonatal health: evidence to date and clinical implications

Karras

Fakhoury

Muscogiuri³

et al. 2016

Therapeutic Advances in Musculoskeletal

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Low maternal vitamin D levels during pregnancy have been associated with a plethora of adverse neonatal outcomes, including small for gestational age and preterm births, detrimental effect on offspring bone and teeth development, and risk of infectious diseases. Although most observational studies indicate a significant linear relationship between maternal 25-hydroxyvitamin D and the above outcomes, some randomized controlled trials to date are inconclusive, mostly due to differences in study design and supplementation regimen. The currently available results indicate that vitamin D supplementation during pregnancy reduces the risk of preterm birth, low birth weight, dental caries of infancy, and neonatal infectious diseases such as respiratory infections and sepsis. This narrative review aims to summarize available trial results regarding the effect of low maternal vitamin D levels during pregnancy, in conjunction with neonatal outcomes on the field, with a discourse on the appropriate clinical approach of this important issue.

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Section: Achieving Adequate Maternal Vitamin D Levelsmentioning

confidence: 99%

Maternal vitamin D levels during pregnancy and neonatal health: evidence to date and clinical implications

Karras

Fakhoury

Muscogiuri³

et al. 2016

Therapeutic Advances in Musculoskeletal

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“…2 ng/mL by LC-MS/MS is of little consequence[1].Additionally, we would like to highlight some important facts. The authors state that one of the strengths of the study was the use of multiple LC-MS/MS methods to obtain an average LC-MS/MS result as the reference value, and that the use of multiple LC-MS/MS methods allowed outlying LC-MS/MS results to be identified and removed, thereby improving the robustness of the reference value[1].…”

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confidence: 98%

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The authors attempt to explain the variation in results obtained with commercial 25-OHD assays.

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confidence: 99%

“…To the Editor, In the recent article by Farrell et al [1], the authors explain the variability in results of various vitamin D (25-OHD) immunoassays based on specific aspects of assay design. Here, we question their interpretation of the conclusion.…”

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confidence: 99%

“…However, inspection of the precision profile in figure 4 demonstrates that other manufacturers had logarithmic fits similar to Siemens. This seems to contradict e130 Donnelly et al: Reply to "Assay design: lessons learned from 25-hydroxyvitamin D" by Farrell et al the statement that the Siemens assay had an atypically flat precision profile that was characterized by an overrecovery of 25-OHD at the lowest concentrations [1]. The 1.2 ng/mL reported by LC-MS/MS is close to the detection capability of LC-MS/MS, thereby producing CVs as high as 20%.…”

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Reply to the article entitled “Impact of assay design on test performance: lessons learned from 25-hydroxyvitamin D” by Farrell et al., Clin Chem Lab Med 2014;52:1579–87

Donnelly¹,

Freeman²,

Wilson³

et al. 2015

Clinical Chemistry and Laboratory Medicine (CCLM)

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Keywords: 25-hydroxyvitamin D; 25-OHD; automated 25-OHD assay; liquid chromatography-tandem mass spectrometry (LC-MS/MS).To the Editor, In the recent article by Farrell et al. [1], the authors explain the variability in results of various vitamin D (25-OHD) immunoassays based on specific aspects of assay design. Here, we question their interpretation of the conclusion.The authors attempt to explain the variation in results obtained with commercial 25-OHD assays. To test their hypotheses, they conducted studies using samples containing 3-epimer 25-OHD, 25-OHD 2 , and human antianimal antibodies. They first tested the hypothesis that assays with one-step release and capture would show superior ability to equally recover 25-OHD 3 and 25-OHD 2 . While the authors acknowledged that none of the immunoassays demonstrated equimolar recovery of 25-OHD 2 and 25-OHD 3 , they found that the DiaSorin assay had the least bias to 25-OHD 2 by liquid chromatography-tandem mass spectrometry (LC-MS/MS). They concluded that these results supported their hypothesis, since only the DiaSorin assay released 25-OHD in the presence of capture by target analyte. We question this conclusion, because they erroneously report in table 4 that the Siemens ADVIA Centaur ® Vitamin D Total (Siemens) assay does not release 25-OHD in the presence of capture moiety. The Siemens assay is performed in one step using sequential reagent additions, not in two steps (which infers a wash step or separation step between critical reagent additions) as observed in some infectious disease assays. Therefore, as vitamin D is released from the vitamin D binding protein (DBP), the capture antibody is present.Another goal of the Farrell et al. article was to examine whether assays that used a backfill assay format (conjugate added in excess in the final incubation) showed superior precision (by amplification of the chemiluminescent signal). Abbott and DiaSorin, but not Roche and Siemens, use the backfill assay format and reportedly showed superior assay precision at higher concentrations. However, Abbott did not show superior precision at lower concentrations, and this was explained by invoking interference by additional unknown variables. As reported in the article, the Siemens assay does not backfill the reagents, yet it demonstrated superior total precision at lower concentrations compared with the DiaSorin and Abbott assays. It would seem that these results refute, rather than support, the hypothesis about backfilling. Backfilling of reagents assumes reagent excess. The Siemens reagents are not in excess. The vitamin D analog and monoclonal antibody specific to 25(OH)vitamin D 2 /D 3 are in fact carefully optimized to obtain both accuracy and precise results. Without rigorous scientific testing to show that the backfill assay format leads to lower imprecision, we question the importance of the backfill assay design and their conclusion.The authors use their hypothesis about backfill and precision to support the discussion of superior DiaSorin assay precision at t...

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A review of chromatographic methods for the determination of water‐ and fat‐soluble vitamins in biological fluids

Karaźniewicz−Łada

Główka

2015

J of Separation Science

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Vitamins are an essential element of nutrition and thus contribute to human health. Vitamins catalyze many biochemical reactions and their lack or excess can cause health problems. Therefore, monitoring vitamin concentrations in plasma or other biological fluids may be useful in the diagnosis of various disorders as well as in the treatment process. Several chromatographic methods have been developed for the determination of these compounds in biological samples, including high-performance liquid chromatography with UV and fluorescence detection. Recently, high-performance liquid chromatography with tandem mass spectrometry methods have been widely used for the determination of vitamins in complex matrices because of their high sensitivity and selectivity. This method requires preconditioning of samples for analysis, including protein precipitation and/or various extraction techniques. The choice of method may depend on the desired cost, convenience, turnaround time, specificity, and accuracy of the information to be obtained. This article reviews the recently reported chromatographic methods used for determination of vitamins in biological fluids. Relevant papers published mostly during the last 5 years were identified by an extensive PubMed search using appropriate keywords. Particular attention was given to the preparation steps and extraction techniques. This report may be helpful in the selection of procedures that are appropriate for certain types of biological materials and analytes.

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Impact of assay design on test performance: lessons learned from 25-hydroxyvitamin D

Abstract: Variations in design among automated 25-OHD assays influence their performance characteristics. Consideration of the details of assay design is therefore important when selecting and validating new assays.

Cited by 15 publications

References 5 publications

Maternal vitamin D levels during pregnancy and neonatal health: evidence to date and clinical implications

Maternal vitamin D levels during pregnancy and neonatal health: evidence to date and clinical implications

Reply to the article entitled “Impact of assay design on test performance: lessons learned from 25-hydroxyvitamin D” by Farrell et al., Clin Chem Lab Med 2014;52:1579–87

A review of chromatographic methods for the determination of water‐ and fat‐soluble vitamins in biological fluids

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