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Development of an Assay to Rapidly Determine Folate Insufficiency in the Field



Many neural tube defects (NTD), serious birth defects of the brain and spine, can be prevented if a woman consumes folic acid daily before and during early pregnancy. Although mandatory folic acid fortification has increased blood folate concentrationsin the U.S., folate insufficiency remains a severe problem on a global scale. Determining the burden of folate insufficiency in a population can help set the stage for large-scale interventions such as food fortification. However, lack of data on blood folate levels hampers public health efforts to identify, intervene, and evaluate populations at risk for NTDs. In addition, many countries have remote and isolated populations, making population-based testing of blood folate levels challenging due to limited access to appropriate laboratories. Dried blood spots (DBS) might be adapted to assess folate status in the field, but use of this technique for collecting, storing, and analyzing folate levels quickly and effectively has not been established.

Project Goal:  The goal of this project is to develop technology to measure blood folate levels, and specifically to develop: 1) an assay that can be used ‘on the spot’ in fieldwork either using DBS or whole blood, or 2) an assay in which the sample is collected in the field and analysis is done in a laboratory within 48 hours.Additional specifications are that 1) the instrument needs to be portable and low maintenance, so it can be used directlyin the field; 2) the maximum volume needed should not exceed 50 uL of blood from a finger stick; 3) the imprecision of the assay should not exceed 10-15% at the clinical decision point of 140 ng/mL of red blood cell folate; and, 4) the assay results have to be comparable to traditionally accepted assays, such as the microbiological assay.

Impact:  The global burden of folate insufficiency as it relates to NTDs has not yet been determined, but is estimated to be over 200,000 pregnancies yearly. This gap in data is primarily because large-scale national surveillancestudies of folate levels and NTDs have not been possible in many countries. Additionally, many countries have remote areas where access to appropriate laboratory facilities is limited or available laboratories have limited capacity for biological testing. An assay that can add data on folate status from remote areas to a country’s surveillance system can allow for an accurate burden of disease estimate. Developmentof these new assays would provide the means to document the folate status of target populations and help determine a course of action to address folate insufficiency programmatically. The expectation is that the proposed technology will meet market demand by laboratories and in-the-field research groups.

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