Race Is an Incomplete Surrogate for Skin Pigmentation in Neonates, with Potential Relevance for Pulse Oximetry

To examine the objective differences and overlap in skin pigment among neonates born to mothers of different racial groups.

We conducted a prospective study assessing neonatal skin tone by spectrophotometry using SkinColorCatch (Delfin, Miami, FL) at the pulse oximetry site (dorsum of foot) in neonatal and cardiac intensive care units. Colorimetric indices were compared between non-Hispanic Black (NHB) and non-Hispanic White (NHW) neonates using Welch's t test. Distribution overlap was evaluated using the overlap coefficient and the probability of a higher value. Bivariate regression assessed the relationships between colorimetric indices and neonatal characteristics, including gestational age and birth weight. A P value of <.05 was considered significant.

Among 100 neonates (33 NHB, 57 NHW, 7 Hispanic, 3 other), skin darkness measures (melanin index, perceived lightness, and individual typology angle [ITA°]) were significantly different between NHB and NHW infants. However, substantial overlap was observed: overlap coefficient of 0.66 (95% CI, 0.51-0.83) for the melanin index and 0.73 (95% CI, 0.57-0.90) for the ITA°. The probability of higher value was 0.27 (melanin index) and 0.69 (ITA°), further demonstrating overlap. Lower gestational age and birth weight correlated with darker skin tone characteristics and this association did not differ significantly by race.

Despite statistical differences, NHB and NHW neonates exhibit substantial overlap in objectively assessed skin color. These findings support the use of direct skin pigmentation measurements in device accuracy studies rather than race-based classifications, helping to decrease bias in medical algorithms and device research.