A method including placing a portion of a foot of a newborn in a device, the device including a light emitter and a corresponding receiver coupled on opposite sides of the device, the device further including a processor for processing data from the light emitter and receiver; and determining a presence of congenital heart disease. An apparatus including a body including a chamber of a size to accommodate a portion of a newborn's foot; at least one light emitter and a corresponding detector coupled on opposite sides of the body, the emitter configured to emit light of a prescribed wavelength into the chamber; and a processor coupled to the body and configured to receive a signal from the at least one detector.