Gel-permeation high-performance liquid chromatography as a powerful technique for rapid analysis of calcitriol (1,25-dihydroxycholecalciferol) receptors.
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ABSTRACT:
SUBMITTER: Danan JL
PROVIDER: S-EPMC1154075 | biostudies-other | 1983 Jan
REPOSITORIES: biostudies-other
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Project description: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.
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