Background: Reference measurement procedures (RMP) have rigorous accuracy specifications. For total 25-hydroxyvitamin D, 25(OH)D, bias ≤1.7% and CV ≤5% are recommended. These quality specifications are impractical for minor analytes, such as 25(OH)D. Furthermore, documentation on RMP quality performance specifications for the individual 25(OH)D metabolites and their daily application are missing.
Methods: To assess accuracy, we used zeta-scores. Daily, 5-10 specimens (duplicate) and 3 reference materials (singleton or duplicate) were measured for 25(OH)D and 25(OH)D using JCTLM-accepted LC-MS/MS RMPs. Protocols were repeated on 3-4 occasions to generate campaign results. We used separate zeta-score acceptability criteria for daily (≤|2|) and campaign (≤|1|) evaluations. Allowable imprecision was determined experimentally.
Results: Across 7 campaigns, unacceptable daily zeta-scores required repeating 2 runs for 25(OH)D and 5 runs for 25(OH)D. Hence, the zeta-scores of acceptable reference material results indicated high accuracy. The allowable imprecision for the RMPs was ≤5% (daily) and ≤ 3% (campaign) for 25(OH)D and ≤ 7% (daily) and ≤ 4% (campaign) for 25(OH)D, respectively.
Conclusions: Using zeta-scores and experimentally derived imprecision, we developed a straightforward approach to assess the acceptability of individual 25(OH)D reference measurements, providing also much-needed practical accuracy specifications for 25(OH)D.
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http://dx.doi.org/10.1016/j.cca.2018.10.006 | DOI Listing |
Curr Issues Mol Biol
December 2024
Department of Neurology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland.
Studies suggest that vitamin D (VitD) may reduce oxidative stress (OS) in multiple sclerosis (MS) patients. This study aimed to compare the effects of various VitD doses on OS in relapsing-remitting MS (RRMS). A 6-month supplementation was introduced using two doses of VitD: 2000 IU/day in the high-dose group (HD, = 23) and 15,960 IU/month in the low-dose group (LD, = 29).
View Article and Find Full Text PDFDiseases
December 2024
Department of Internal Medicine, Hospital Civil de Guadalajara Fray Antonio Alcalde, Guadalajara 44280, JAL, Mexico.
Background And Objectives: The correlation between diminished 25-hydroxyvitamin D (25-(OH)D) concentrations and heightened disease activity in systemic lupus erythematosus (SLE) patients remains contentious, as clinical studies have yielded conflicting outcomes-some propose a potential link, while others assert no relationship exists. Nonetheless, all studies report a significant prevalence of low 25-(OH)D levels among SLE patients. This study aimed to assess the frequency of low serum levels of 25-(OH)D in Mexican patients with SLE and to evaluate the correlation between 25-(OH)D deficiency or insufficiency and disease activity levels.
View Article and Find Full Text PDFEpidemiologia (Basel)
December 2024
Cluster of Competency " Environment and Health", Faculty of Sciences, Moulay Ismail University, Meknes 50000, Morocco.
Vitamin D and iron deficiencies are prevalent among Moroccan women of reproductive age (WRA). Research suggests that Vitamin D deficiency (VDD) may impair iron bioavailability, potentially leading to iron deficiency (ID) and anemia. Objectives: This study investigates associations between vitamin D status, iron levels, and anemia risk in WRA, aged 18-49, from Meknes, Morocco.
View Article and Find Full Text PDFActa Paediatr
December 2024
Department of Medicine, Paediatric Outpatient Clinic, Helgeland Hospital, Sandnessjøen, Norway.
Aim: Vitamin D is crucial for the immune system, as it enhances pathogen-fighting cells and reduces inflammation. We reviewed serum 25-hydroxyvitamin D (25(OH)D) concentrations in children with viral upper respiratory tract infections (URTIs) and the impact of vitamin D supplements on those infections.
Methods: A mini literature review was conducted from 1 January 2000 to 30 April 2024.
Clin Endocrinol (Oxf)
December 2024
Department of Medicine, University of Auckland, Auckland, New Zealand.
Objective: Vitamin D deficiency (VDD) in children can cause hypocalcaemia and rickets, but the prevalence of these complications and the 25-hydroxyvitamin D (25OHD) concentrations below which they arise is uncertain. We investigated this in children (< 18 years) with 25OHD measurements.
Design, Measurement And Patients: We obtained 25OHD results from the regional laboratory database, alongside albumin-adjusted serum calcium (aCa), parathyroid hormone (PTH) and alkaline phosphatase (ALP) within 6 months of the index 25OHD.
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