Publications by authors named "F Ivison"
Rationale & Objective: Kidneys are vital for vitamin D metabolism, and disruptions in both production and catabolism occur in chronic kidney disease. Although vitamin D activation occurs in numerous tissues, the kidneys are the most relevant source of circulating active vitamin D. This study investigates extrarenal vitamin D activation and the impact of kidney transplantation on vitamin D metabolism in patients who are anephric.
View Article and Find Full Text PDFBackground: Laboratories are recommended to use patient data to derive their local adjusted calcium (adjCa) equation, using numerous criteria to exclude patients with potential calcium metabolism abnormalities. It is not known which, if any, of the exclusions influence the final equation formula, or to what extent. This study investigated the effect using fewer exclusions has on adjCa equations and on patient results when compared to a reference equation.
View Article and Find Full Text PDFArticle Synopsis
- The Vitamin D External Quality Assessment Scheme (DEQAS) sends human serum samples to over 1000 global participants to measure total serum 25-hydroxyvitamin D levels four times a year.
- A study was conducted to determine if shipping these samples at ambient temperature affects the reliability of various 25(OH)D assays compared to shipping them frozen.
- Results showed significant differences for four specific assays when samples were shipped ambiently, but all 14 LC-MS/MS assays showed no significant differences, indicating they remained stable during shipping at room temperature.
An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of liquid chromatography - tandem mass spectrometry (LC-MS/MS) assays used for the determination of serum total 25-hydroxyvitamin D (25(OH)D), which is the sum of 25-hydroxyvitamin D (25(OH)D) and 25-hydroxyvitamin D (25(OH)D). A set of 50 single-donor samples was assigned target values for concentrations of 25(OH)D, 25(OH)D, 3-epi-25-hydroxyvitamin D (3-epi-25(OH)D), and 24R,25-dihydroxyvitamin D (24R,25(OH)D) using isotope dilution liquid chromatography - tandem mass spectrometry (ID LC-MS/MS). VDSP Intercomparison Study 2 Part 1 includes results from 14 laboratories using 14 custom LC-MS/MS assays.
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- - An interlaboratory study was conducted by the Vitamin D Standardization Program (VDSP) to evaluate how well Standard Reference Materials (SRMs) and proficiency testing samples can be used interchangeably for measuring serum total 25-hydroxyvitamin D levels using different assay methods.
- - A total of 50 single-donor serum samples were tested across 28 laboratories using a mix of 20 ligand binding assays and 14 LC-MS/MS methods, with target values assigned based on reference measurement procedures.
- - Results showed that certain SRM and proficiency testing samples were found to be non-commutable for specific assays, particularly indicating that SRM 972a (with high 3-epi-25(OH)