Erythrocyte and Serum Folate Collection Techniques: A Multi-Method Study of Folate Status

Abstract

Introduction: Public health programs aimed at identifying and monitoring individuals at risk of specific nutrient deficiencies may benefit from advances in biospecimen sampling techniques that allow for easier in-the-field collections. Such advances may be particularly important for those of childbearing potential, in order to identify individuals at risk of low folate status due to sub-optimal nutriture. Folate is a critical nutrient of interest among women of childbearing potential because suboptimal levels are a primary contributor to neural tube defects. Whatman Paper Dried Blood Spots (WDBS) are a convenient method for assessing folate; however, a major drawback of WDBS has been the inability to separate serum from erythrocyte folate in these samples. Aim of study: The purpose of this study was to test the feasibility of using newer linear flow chromatography DBS cards to measure serum and erythrocyte folate. Method: A convenience sample (n=27) was recruited to assess folate values collected by venous blood draw, Whatman paper, and linear flow chromatography cards. These sampling techniques allowed for assessment of erythrocyte and serum folate values collected via different methods. Folate levels in the samples were assessed using standard Lactobacillus casei microbiological assays. Results: Erythrocyte folate values from the two blood spot methodologies (Whatman paper and linear flow chromatography DBS) indicate a strong linear relationship, with 92% of variance accounted for in a linear regression analysis. Similarly, venous blood samples and linear flow chromatography DBS values accounted for 88% of the variance. Conclusion: Linear flow chromatography dried blood spot cards are useful for assessment of erythrocyte and serum folate. Values had a strong, positive, linear relationship to serum and erythrocyte folate values from other validated methodologies, including Whatman dried blood spots and venous whole blood samples.