A system (10) and method of measuring hemoglobin and bilirubin parameters in a whole blood sample using optical absorbance. The system (10) includes an optical-sample module (20), a spectrometer module (100), an optical fiber assembly (90) optically connecting the optical-sample module (20) to the spectrometer module (100), and a processor module (150). The optical-sample module (20) has a light-emitting module (22) having a LED light source (28), a cuvette assembly (40) and a calibrating-light module (60). The processor module (150) receives and processes an electrical signal from the spectrometer module (100) and transforms the electrical signal into an output signal useable for displaying and reporting hemoglobin parameter values and/or total bilirubin parameter values for the whole blood sample.
