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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

Bland-Altman plot showing the bias between the automated method and the mean of the two methods on a percentage basis.
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fig5: Bland-Altman plot showing the bias between the automated method and the mean of the two methods on a percentage basis.

Mentions: The mean bias with respect to the mean of the two methods was −3.8 (1.96 SD, −28.3 to 20.8) pg/mL for the LC-MS/MS method minus the automated assay (Figure 4). The limits of agreement, expressed as a percentage of the 1.96 SD of mean between the methods, were very large (Figure 5). Particularly, with the LC-MS/MS method, a large downward deviation from the mean of the two methods was obvious in several samples.


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)

Bland-Altman plot showing the bias between the automated method and the mean of the two methods on a percentage basis.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig5: Bland-Altman plot showing the bias between the automated method and the mean of the two methods on a percentage basis.
Mentions: The mean bias with respect to the mean of the two methods was −3.8 (1.96 SD, −28.3 to 20.8) pg/mL for the LC-MS/MS method minus the automated assay (Figure 4). The limits of agreement, expressed as a percentage of the 1.96 SD of mean between the methods, were very large (Figure 5). Particularly, with the LC-MS/MS method, a large downward deviation from the mean of the two methods was obvious in several samples.

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