An optical-sample module capable of being installed in a COOx system that measures whole-blood hemoglobin parameters or whole-blood bilirubin parameters, the optical-sample module comprising a calibrating-light module and a cuvette assembly having a sample receiving chamber adapted for receiving a whole-blood sample, the calibrating-light module comprising: a calibrating module housing; a light beam receiving portion connected to a first end of the calibrating module housing, the light beam receiving portion being aligned with a light beam from a light-emitting module that defines an optical path of the COOx system; a calibrating light portion having a calibrating light source that is configured to direct a calibrating light transversely toward the optical path; a beam splitter disposed in the optical path and positioned to receive the calibrating light from the calibrating light portion and to direct it into and along the optical path; and an optic fiber portion at a second end of the calibrating module housing and including an optical fiber connector assembly with a connector housing adapted to receive an optical fiber assembly for optically connecting the optical-sample module to a spectrometer module of the COOx system, whereby the beam splitter is disposed between the light beam receiving portion and the optic fiber portion and directs the calibrating light towards the optic fiber portion, wherein the sample receiving chamber, the calibrating module housing, the light beam receiving portion and the optic fiber portion are positioned within the optical path and the calibrating light portion is spaced from the optical path, and wherein the calibrating-light module is arranged downstream from the cuvette assembly along the optical path. the calibrating-light module comprising: a calibrating module housing; a light beam receiving portion connected to a first end of the calibrating module housing, the light beam receiving portion being aligned with a light beam from a light-emitting module that defines an optical path of the COOx system; a calibrating light portion having a calibrating light source that is configured to direct a calibrating light transversely toward the optical path; a beam splitter disposed in the optical path and positioned to receive the calibrating light from the calibrating light portion and to direct it into and along the optical path; and an optic fiber portion at a second end of the calibrating module housing and including an optical fiber connector assembly with a connector housing adapted to receive an optical fiber assembly for optically connecting the optical-sample module to a spectrometer module of the COOx system, whereby the beam splitter is disposed between the light beam receiving portion and the optic fiber portion and directs the calibrating light towards the optic fiber portion, wherein a calibrating module housing; a light beam receiving portion connected to a first end of the calibrating module housing, the light beam receiving portion being aligned with a light beam from a light-emitting module that defines an optical path of the COOx system; a calibrating light portion having a calibrating light source that is configured to direct a calibrating light transversely toward the optical path; a beam splitter disposed in the optical path and positioned to receive the calibrating light from the calibrating light portion and to direct it into and along the optical path; and an optic fiber portion at a second end of the calibrating module housing and including an optical fiber connector assembly with a connector housing adapted to receive an optical fiber assembly for optically connecting the optical-sample module to a spectrometer module of the COOx system, whereby the beam splitter is disposed between the light beam receiving portion and the optic fiber portion and directs the calibrating light towards the optic fiber portion, wherein the sample receiving chamber, the calibrating module housing, the light beam receiving portion and the optic fiber portion are positioned within the optical path and the calibrating light portion is spaced from the optical path, and wherein the calibrating-light module is arranged downstream from the cuvette assembly along the optical path.