A method of operating an analytical laboratory is presented. The method comprises the steps of: setting a load limit for each laboratory instrument at maximum instrument capacity; dispatching biological samples to laboratory instrument(s) at a dispatch rate not greater than the instrument load limit; each laboratory instrument sending test order queries to the laboratory middleware upon identifying a biological sample; in response to the test order queries transmitting test orders to the laboratory instruments corresponding to the biological samples; the laboratory middleware monitoring a query rate of the plurality of laboratory instruments in order to determine an effective flow rate corresponding to each laboratory instrument; decreasing the load limit of a first laboratory instrument if its effective flow rate is lower than the dispatch rate; increasing the load limit for the first laboratory instrument if its effective flow rate is greater than or equal to the dispatch rate.