A total hemoglobin index system derives total hemoglobin (tHb) index value utilizing a depopulated emitter with an index set of LEDs. A patient fails a tHb index test if tHb measurements are trending down and/or tHb values fall below a predefined index threshold. If a patient fails the tHb index test, a high resolution sensor derives a specific tHb measurement utilizing a high resolution set of LEDs. The number of high resolution set LEDs is greater than the number of index set LEDs.