A method of operating an analytical laboratory, comprising the steps of: a) receiving and identifying a plurality of biological samples held in sample containers and sorting the plurality of sample containers into a sample rack by a pre-analytical laboratory instrument of the analytical laboratory; b) retrieving an order list A from a storage unit, the order list A comprising a plurality of test orders corresponding to the sample containers within the respective sample rack; each test order defining at least one processing step to be carried out on the biological sample held in the respective sample container; c) determining an optimal transportation route by the control unit for the sample rack based on the order list A, a set of constraints and an objective function, the transportation route being indicative of a list and/or sequence of laboratory instrument(s) required to complete one or more of the test orders of the order list A; d) re-determining the optimal transportation route by the control unit upon a change of one or more of the set of constraints and/or a change of the objective function; e) transporting the sample rack to one or more of the plurality of laboratory instruments according to the optimal transportation route by the sample transportation system; f) processing the biological samples according to the corresponding test orders by the target laboratory instrument(s), wherein the step of determining respectively re-determining the optimal transportation route by the control unit comprises the steps of: i) retrieving a route list B of all available transportation routes of the sample transportation system; ii) determining one or more route instrument list(s) C for each transportation route of the route list B, the route instrument list C comprising laboratory instruments reachable by the respective transportation route; iii) determining an instrument list D of all laboratory instruments required to process all sample containers within the respective sample rack according to the order list A; iv) discarding from the route list B any transportation route(s) that does not contain any laboratory instrument(s) of the instrument list D; v) determining the optimum transportation route from route list B by the objective function, wherein the objective function determines as optimum transportation route, the transportation route from route list B which comprises most laboratory instruments of instrument list D. a) receiving and identifying a plurality of biological samples held in sample containers and sorting the plurality of sample containers into a sample rack by a pre-analytical laboratory instrument of the analytical laboratory; b) retrieving an order list A from a storage unit, the order list A comprising a plurality of test orders corresponding to the sample containers within the respective sample rack; each test order defining at least one processing step to be carried out on the biological sample held in the respective sample container; c) determining an optimal transportation route by the control unit for the sample rack based on the order list A, a set of constraints and an objective function, the transportation route being indicative of a list and/or sequence of laboratory instrument(s) required to complete one or more of the test orders of the order list A; d) re-determining the optimal transportation route by the control unit upon a change of one or more of the set of constraints and/or a change of the objective function; e) transporting the sample rack to one or more of the plurality of laboratory instruments according to the optimal transportation route by the sample transportation system; f) processing the biological samples according to the corresponding test orders by the target laboratory instrument(s), i) retrieving a route list B of all available transportation routes of the sample transportation system; ii) determining one or more route instrument list(s) C for each transportation route of the route list B, the route instrument list C comprising laboratory instruments reachable by the respective transportation route; iii) determining an instrument list D of all laboratory instruments required to process all sample containers within the respective sample rack according to the order list A; iv) discarding from the route list B any transportation route(s) that does not contain any laboratory instrument(s) of the instrument list D; v) determining the optimum transportation route from route list B by the objective function,