A method of determining a physical property of a biological sample (204,204'), wherein the method comprises the steps of: - acquiring a set of preliminary calibration signals of a first lot of a reagent using an automatic analyzer according to a calibration protocol, wherein the automatic analyzer acquires the preliminary calibration signals using a first photometry module; - acquiring a reference set of signals of the first lot of the reagent using a calibration analyzer according to the calibration protocol, wherein the calibration analyzer acquires the reference set of signals using a second photometry module; - determining a set of module specific components by subtracting the reference set of signals from the preliminary calibration signals; - acquiring a lot specific set of signals of a second lot of the reagent using the second photometry module of the calibration analyzer according to the calibration protocol; - determining a lot calibration for the first photometry module using the set of module specific components and the lot specific set of signals; and - acquiring a measurement signal of the biological sample using the first photometry module of the automatic analyzer and the second lot of the reagent; and - determining a physical property of the biological sample (204,204') using the measurement signal and the lot calibration; wherein any one of the following: • wherein the step of determining the lot calibration for the first photometry module comprises adding the set of module specific components to the lot specific set of signals; • wherein the method further comprises the step of: calculating a calibration constant by dividing the set of module specific components by the reference set of signals, wherein the determination of the lot calibration for the first photometry module is determined by multiplying the quantity 1 plus the calibration constant by the lot specific set of signals; and • wherein the method further comprises the step of: calculating a linear fit between the module specific components and the reference set of signals, wherein the linear fit comprises a calibration constant and an offset constant, wherein the determination of the lot calibration for the first photometry module is determined by adding the offset constant to the product of the calibration constant and the lot specific set of signals. - acquiring a set of preliminary calibration signals of a first lot of a reagent using an automatic analyzer according to a calibration protocol, wherein the automatic analyzer acquires the preliminary calibration signals using a first photometry module; - acquiring a reference set of signals of the first lot of the reagent using a calibration analyzer according to the calibration protocol, wherein the calibration analyzer acquires the reference set of signals using a second photometry module; - determining a set of module specific components by subtracting the reference set of signals from the preliminary calibration signals; - acquiring a lot specific set of signals of a second lot of the reagent using the second photometry module of the calibration analyzer according to the calibration protocol; - determining a lot calibration for the first photometry module using the set of module specific components and the lot specific set of signals; and - acquiring a measurement signal of the biological sample using the first photometry module of the automatic analyzer and the second lot of the reagent; and - determining a physical property of the biological sample (204,204') using the measurement signal and the lot calibration; • wherein the step of determining the lot calibration for the first photometry module comprises adding the set of module specific components to the lot specific set of signals; • wherein the method further comprises the step of: calculating a calibration constant by dividing the set of module specific components by the reference set of signals, wherein the determination of the lot calibration for the first photometry module is determined by multiplying the quantity 1 plus the calibration constant by the lot specific set of signals; and • wherein the method further comprises the step of: calculating a linear fit between the module specific components and the reference set of signals, wherein the linear fit comprises a calibration constant and an offset constant, wherein the determination of the lot calibration for the first photometry module is determined by adding the offset constant to the product of the calibration constant and the lot specific set of signals.