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Measurement of Circulating 1,25-Dihydroxyvitamin D: Comparison of an Automated Method with a Liquid Chromatography Tandem Mass Spectrometry Method.

Zittermann A, Ernst JB, Becker T, Dreier J, Knabbe C, Gummert JF, Kuhn J - Int J Anal Chem (2016)

Bottom Line: Background.In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit.Results.

View Article: PubMed Central - PubMed

Affiliation: Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, 32545 Bad Oeynhausen, Germany.

ABSTRACT
Background. The clinical relevance of circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) is probably underappreciated, but variations in the measurement of this difficult analyte between different methods limit comparison of results. Methods. In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit. Results. Median (interquartile range) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5-39.0 pg/mL) and 23.6 pg/mL (16.1-31.3 pg/mL), respectively (P = 0.001). Using the method-specific cut-offs for deficient 1,25(OH)2D levels (<20 pg/mL for the automated assay and <17 pg/mL for the LC-MS/MS method), the percentage of patients classified as 1,25(OH)2D deficient was 28.7% and 27.1%, respectively. However, concordance between the two methods for deficient levels was only 62% and the concordance correlation coefficient was poor (0.534). The regression equation resulted in an intercept of -1.99 (95% CI: -7.33-1.31) and a slope of 1.27 (95% CI: 1.04-1.52) for the automated assay. The mean bias with respect to the mean of the two methods was -3.8 (1.96 SD: -28.3-20.8) pg/mL for the LC-MS/MS method minus the automated assay. Conclusions. The two methods show only modest correlation and further standardization is required to improve reliability and comparability of 1,25(OH)2D test procedures.

No MeSH data available.


Related in: MedlinePlus

Box and whisker plots showing the distribution of results for the automated assay and the LC-MS/MS method. The central boxes express the upper and lower quartile, and the central lines show the median. The whiskers represent the values below and above the interquartiles, excluding outliers. Outliers (circles) are defined as values that exceed the upper and lower quartile plus or minus 1.5 times the interquartile range.
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fig1: Box and whisker plots showing the distribution of results for the automated assay and the LC-MS/MS method. The central boxes express the upper and lower quartile, and the central lines show the median. The whiskers represent the values below and above the interquartiles, excluding outliers. Outliers (circles) are defined as values that exceed the upper and lower quartile plus or minus 1.5 times the interquartile range.

Mentions: The 129 patients had a median age of 73 years (IQR: 64–79 years; range: 34 to 89 years), and 32.3% were females. Box and whisker plots showing the distribution of the results of the two methods are given in Figure 1. Median (IQR) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5–39.0 pg/mL) and 23.6 pg/mL (16.1–31.3 pg/mL), respectively (P = 0.001).


Measurement of Circulating 1,25-Dihydroxyvitamin D: Comparison of an Automated Method with a Liquid Chromatography Tandem Mass Spectrometry Method.

Zittermann A, Ernst JB, Becker T, Dreier J, Knabbe C, Gummert JF, Kuhn J - Int J Anal Chem (2016)

Box and whisker plots showing the distribution of results for the automated assay and the LC-MS/MS method. The central boxes express the upper and lower quartile, and the central lines show the median. The whiskers represent the values below and above the interquartiles, excluding outliers. Outliers (circles) are defined as values that exceed the upper and lower quartile plus or minus 1.5 times the interquartile range.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4835639&req=5

fig1: Box and whisker plots showing the distribution of results for the automated assay and the LC-MS/MS method. The central boxes express the upper and lower quartile, and the central lines show the median. The whiskers represent the values below and above the interquartiles, excluding outliers. Outliers (circles) are defined as values that exceed the upper and lower quartile plus or minus 1.5 times the interquartile range.
Mentions: The 129 patients had a median age of 73 years (IQR: 64–79 years; range: 34 to 89 years), and 32.3% were females. Box and whisker plots showing the distribution of the results of the two methods are given in Figure 1. Median (IQR) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5–39.0 pg/mL) and 23.6 pg/mL (16.1–31.3 pg/mL), respectively (P = 0.001).

Bottom Line: Background.In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit.Results.

View Article: PubMed Central - PubMed

Affiliation: Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, 32545 Bad Oeynhausen, Germany.

ABSTRACT
Background. The clinical relevance of circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) is probably underappreciated, but variations in the measurement of this difficult analyte between different methods limit comparison of results. Methods. In 129 clinical samples, we compared a new automated assay with a commercially available liquid chromatography tandem mass spectrometry (LC-MS/MS) kit. Results. Median (interquartile range) 1,25(OH)2D concentrations with the automated assay and the LC-MS/MS method were 26.6 pg/mL (18.5-39.0 pg/mL) and 23.6 pg/mL (16.1-31.3 pg/mL), respectively (P = 0.001). Using the method-specific cut-offs for deficient 1,25(OH)2D levels (<20 pg/mL for the automated assay and <17 pg/mL for the LC-MS/MS method), the percentage of patients classified as 1,25(OH)2D deficient was 28.7% and 27.1%, respectively. However, concordance between the two methods for deficient levels was only 62% and the concordance correlation coefficient was poor (0.534). The regression equation resulted in an intercept of -1.99 (95% CI: -7.33-1.31) and a slope of 1.27 (95% CI: 1.04-1.52) for the automated assay. The mean bias with respect to the mean of the two methods was -3.8 (1.96 SD: -28.3-20.8) pg/mL for the LC-MS/MS method minus the automated assay. Conclusions. The two methods show only modest correlation and further standardization is required to improve reliability and comparability of 1,25(OH)2D test procedures.

No MeSH data available.


Related in: MedlinePlus