Quantification of 25-hydroxyvitamin D3 in dried blood spots as compared to plasma among Indian adults

Abstract

Background Vitamin D may play an important role in later-life physical and cognitive health. Vitamin D status is standardly assessed in serum and plasma; however, collection, transport, and storage costs make large epidemiologic studies challenging. We assessed the agreement of 25-hydroxyvitamin D3 (25(OH)D3) quantification from dried blood spots (DBS) as compared to standard plasma assessment among older Indian adults. Methods A total of 58 adults over 45 years of age who resided in Pune, India were enrolled in the study from July 2020 to June 2021. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to assess 25(OH)D3 concentrations in paired plasma and DBS samples. Results Plasma and DBS 25(OH)D3 concentrations were highly correlated (Pearson’s correlation = 0.976). The median 25(OH)D3 concentration of the study population assessed by plasma was 14.6 ng/mL (Q1=12.0, Q3= 18.1) while the median concentration assessed in DBS was 12.8 ng/mL (Q1=11.0, Q3= 16.6). 25(OH)D3 concentrations measured from DBS were on average 6% (95% CI: 2-13%) lower than concentrations assessed by plasma across the observed 25(OH)D3 distribution. Conclusions We found good agreement between 25(OH)D3 quantification between DBS and plasma and our findings indicate that DBS can be used in epidemiologic studies of vitamin D among Indian adults.