Validation of summer and winter ELISA measurements of serum 25-hydroxyvitamin D concentrations in Mongolia.

Background And Objectives: Assay cost, quality, and availability pose challenges for vitamin D surveys in limited resource settings. This study aimed to validate an inexpensive vitamin D assay (ELISA) under real-world conditions in Mongolia, the northernmost developing country, to characterize the assay's usefulness and inform the design of epidemiologic studies in similar regions.

Methods And Study Design: We collected paired summer and winter serum samples from 120 men and women (aged 20-57 years) in urban and rural Mongolia, analyzed each sample for 25(OH)D concentration using both Immunodiagnostic Systems ELISA and DiaSorin LIAISON 25(OH)D TOTAL, and compared the assays using multiple statistics.