Evaluation of Light-Emitting Diodes for Whole Blood Oximetry

The difference between the optical extinction coefficients of oxy-and deoxyhemoglobin is a primary concern in the design of blood oxygen instrumentation. In this communication, we report the apparent values for the molar extinction coefficients of hemoglobin under conditions of interest to instrument designers, namely, with whole blood and with unfiltered LED illumination. Extinction coefficient values are reported for four commercially available LED's with typical spectral half-intensity bandwidths and peak emissions ranging from 660 to 940 nm.