PROJECT SUMMARY/ABSTRACT We propose to assess the correlation between arterial oxygen saturation (SaO2) and peripheral oxygen saturation measured by pulse oximetry (SpO2) discrepancy and skin pigmentation. Recent data demonstrated that pulse oximetry devices overestimate SpO2 in darker skin adults. This is less understood in newborns. However, medical conditions associated with hypoxemia occur more commonly in black infants and the conditions associated with hyperoxemia occur less frequently in black infants. Thus, raising the question if pulse oximeters overestimate SpO2 in black infants and falsely putting them in the “safe” zone. We will measure simultaneous SaO2 and SpO2 among varying degrees of skin pigmentation while accounting for other physiologic variables such as gestational age, receipt of red blood cells, bilirubin, and sex, to assess the impact of skin pigmentation on the SaO2-SpO2 discrepancy. Members of our team have experience with research related to oxygen targeted therapies and pulse oximetry in newborns. Additionally, our team members have experience working with recorded pulse oximetry data and have received support from the leading pulse oximeter device company to supply equipment and sensors for this proposal. The proposed research is significant because it will answer the question if pulse oximetry bias due to skin color occurs to a degree that is clinically significant and could cause harm for newborns with darker skin. Results from this study will inform a larger trial in which we will assess the effect of postnatal age on pulse oximetry accuracy and multiple oximeters and will impact how pulse oximetry is used for infants of varying skin color in routine care such CCHD screening, SpO2 targeted care and future clinical trials. Additionally, this is innovative because it will use readily available SpO2 and SaO2 measurements from infants with varying degrees of light and dark skin to assess pulse oximeter bias and imprecision and will use a noninvasive device to measure melanin index to quantify skin pigmentation. Additionally, it will take into consideration other physiologic impacts on SpO2 such as gestational age, degree of hypoxemia, gender, and red blood cell transfusion. Through collaboration between two neonatal intensive care units, we will establish the infrastructure and necessary multidisciplinary relationships that can later be expanded to conduct future multicenter studies to evaluate the potential disparity from pulse oximeters and how it correlates with skin pigmentation.