An oximeter sensor system includes a light source group having a plurality of LEDs including at least a first visible light LED, a second visible light LED and an infrared LED adjacent the first visible light LED and the second visible light LED, an infrared filter disposed in front of only the first visible light LED and the second visible light LED, a light source housing having a base, one or more sidewalls and a light-emitting end where the light source housing has a frustum shape where the light source group is disposed adjacent the base and facing the light-emitting end and where the one or more sidewalls has a reflective coating thereon, a light detector disposed opposite to, spaced from and facing the light-emitting end of the light source housing, and a cuvette disposed between the light-emitting end of the light source housing and the light detector.