MSACL 2026 Abstract

From Clinical Validation to Nationwide Monitoring: Capillary Dried Blood Spots for Vitamin D Assessment in the Latest Belgian Food Consumption Survey

Ghesquière Rosalie (1), Heughebaert Liesl (1), Berger Nicolas (2), Isabelle Moyersoen (2), Christophe Stove (1)
(1) Ghent University, Ghent, Belgium (2) Scientific Institute of Public Health (Sciensano), Brussels, Belgium

Rosalie Ghesquière, Master of Science in Drug Development (Presenter) Laboratory of Toxicology - Ghent University

Presenter Bio: Rosalie Ghesquière graduated as a pharmacist from Ghent University (Belgium), where she obtained her Master’s degree in Drug Development in 2024. That same year, she started her PhD at the Laboratory of Toxicology, led by Professor Christophe Stove. Her doctoral research focuses on epidemiological studies, including the development and application of LC-MS/MS-based methods for small molecules, as well as the analysis of protein adducts (hemoglobin and human serum albumin) as long-term biomarkers of environmental exposure.

Relevant Financial Disclosures (within past 24 months, reported on Apr 16, 2026) No relevant financial relationship(s) to disclose. Conflict mitigation NOT REQUIRED.

INTRODUCTION:
Vitamin D deficiency has been associated with a wide range of chronic diseases, underscoring the importance of generating reliable epidemiological data. However, large-scale population monitoring remains challenging because of the reliance on venous blood sampling, which is invasive and logistically demanding. Emerging microsampling technologies offer a practical alternative by enabling minimally invasive, decentralized, and participant-friendly sample collection, thereby creating new opportunities for large-scale biomarker-based studies. Within this context, capillary dried blood spot (cDBS) sampling was implemented in the most recent Belgian National Food Consumption Survey to enable nationwide assessment of vitamin D status. Although the LC-MS/MS-method for 25-hydroxyvitamin D (25-(OH)D) quantification had been previously analytically validated, clinical validation was required to assess the agreement between DBS and the reference matrix, plasma, prior to large-scale implementation.

METHODS:
Venous plasma and whole blood, venous DBS (vDBS), and cDBS were collected from 44 healthy volunteers to evaluate agreement between matrices. A hematocrit (Hct)-dependent conversion factor was applied to transform cDBS results to plasma-equivalent concentrations. For this, we evaluated four different Hct determination approaches: the reference Hct obtained from liquid whole blood using a hematology analyzer, two non-contact cDBS based prediction technologies relying on near-infrared (NIR) and ultraviolet-visible (UV Vis) spectroscopy, and a general gender specific population-based Hct. All samples were analysed using validated LC-MS/MS methods. Following successful clinical validation, the optimized approach was applied to 793 cDBS samples collected in the context of the most recent Belgian National Food Consumption Survey.

RESULTS:
The clinical validation revealed no clinically relevant methodological (vDBS vs. whole blood) or sampling-site related (cDBS vs. vDBS) differences. After Hct-dependent conversion, strong agreement between cDBS-derived plasma concentrations and measured plasma concentrations was demonstrated, with 90% of results within 20% of the plasma value, independent of the Hct approach. Weighted Cohen’s kappa values (0.83-0.85) indicated substantial to almost perfect agreement in vitamin D status classification. Application of the method to the survey samples revealed a considerable prevalence of vitamin D deficiency, with 42% of participants presenting 25-(OH)D3 concentrations below 20 ng/mL, underscoring the public health relevance of reliable nationwide monitoring.

CONCLUSION:
Capillary DBS, following Hct-dependent conversion, are a reliable and practical alternative to plasma for large-scale vitamin D assessment. By enabling decentralized and minimally invasive sampling, this emerging microsampling approach supports large-scale implementation in population-based studies, as evidenced by its successful integration into the latest Belgian National Food Consumption Survey.