Method for calibrating clinical chemistry instruments

A method of calibrating an optical system of a clinical chemistry instrument, the optical system including at least one light source and a light detector, the at least one light source emitting light to illuminate an object, the illuminated object reflecting light, the light detector receiving light reflected by the object illuminated by the light from the at least one light source, the light detector providing a signal in response to light received by the light detector, the method comprising the steps of:

• causing the at least one light source to emit light;
• measuring a wavelength band shape and centroid wavelength of the light emitted by the at least one light source for a predetermined wavelength band of light emitted by the at least one light source to provide a measured wavelength band shape and measured centroid wavelength;
• subtracting the measured centroid wavelength of light emitted by the at least one light source at the measured wavelength band shape from a reference centroid wavelength having a reference wavelength band shape which is substantially the same as the measured wavelength band shape and determining thereby a baseline correction value and a sensitivity correction value for the optical system being calibrated, the baseline correction value and the sensitivity correction value defining a correction which is used to modify the reflection density of the object determined from the signal provided by the light detector.