SUMMARY Lead (Pb) poisoning remains a global public health crisis and is responsible for 30% of the global burden of idiopathic intellectual disability, according to the World Health Organization (WHO). Exposure to lead during fetal and early child development can have significant structural and functional effects on the brain and other organ systems, and early symptoms of lead poisoning like neurological impairment and behavior disorders are hard to identify. The CDC has declared that no level of Pb exposure is safe for children, yet the vast majority of newborns, infants, and children in the US are not tested. A major limitation of current diagnostic testing for measuring blood lead levels (BLL) is that it requires venous blood. Venipuncture is technically difficult to implement on infants, and it is a frightening procedure for young children, which serve as an obstacle to Pb screening. This has led to less than half of children under 6 years of age currently being tested for Pb exposures in the US. As a result, there is a critical unmet need for new approaches to Pb screening in early life to identify at-risk individuals and inform remediation efforts to remove or reduce Pb exposures during critical stages of human development. In this Phase I STTR application we will optimize and validate a metals-free dried blood spot (DBS) collection device to accurately quantify low BLLs in a single drop of capillary blood collected on filter paper. Our approach features the following innovative and patented technology: (1) A process to remove Pb contamination from filter paper before blood is collected, (2) A device to protect the filter paper from environmental Pb contamination before, during, after blood collection, and (3) The use of discs of filter paper with known blood saturation volumes to allow for accurately and precisely blood volume estimates, while simplifying blood extraction procedures in the laboratory. Our approach combines the low cost and burden of capillary blood sampling with rigorous quantification of BLLs in the lab. Successful completion of these study aims will result in a simple, low-cost, and minimally-invasive blood collection device that can quantify BLLs with precision and detection limits similar to gold standard venipuncture methods. This will provide new market opportunities to expand Pb testing in newborn, infant, and children populations.