A fluidic system comprising: a transport medium pumping system (110; 327); a fluidic conduit adapted and configured to transport an analytical stream comprising the transport medium; a sample injection means adapted and configured to introduce a sample into the transport medium; a first reagent injector adapted and configured to inject a first reagent into the transport medium; a first reaction device coupled to the fluidic conduit, arranged to contain a first analyte produced by a reaction in the analytical stream between the sample and the first reagent; a sample detection module comprising an analyte detector downstream of the first reaction device; and characterised in that: the sample is introduced into the analytical stream; the first reagent is injected into the analytical stream, and the first reaction device is downstream of the first reagent injector and of the sample introduction means; and in that the pumping system comprises a flow control module adapted and configured to maintain a constant flow rate of the analytical stream at the analyte detector, comprising: - a transport medium flow sensor; - a transport medium flow rate adjuster; and - a controller arranged to adjust the adjuster to control the flow of transport medium to compensate for the sample and the reagent introduced into the analytical stream. a transport medium pumping system (110; 327); a fluidic conduit adapted and configured to transport an analytical stream comprising the transport medium; a sample injection means adapted and configured to introduce a sample into the transport medium; a first reagent injector adapted and configured to inject a first reagent into the transport medium; a first reaction device coupled to the fluidic conduit, arranged to contain a first analyte produced by a reaction in the analytical stream between the sample and the first reagent; a sample detection module comprising an analyte detector downstream of the first reaction device; and characterised in that: the sample is introduced into the analytical stream; the first reagent is injected into the analytical stream, and the first reaction device is downstream of the first reagent injector and of the sample introduction means; and in that the pumping system comprises a flow control module adapted and configured to maintain a constant flow rate of the analytical stream at the analyte detector, comprising: - a transport medium flow sensor; - a transport medium flow rate adjuster; and - a controller arranged to adjust the adjuster to control the flow of transport medium to compensate for the sample and the reagent introduced into the analytical stream. the sample is introduced into the analytical stream; the first reagent is injected into the analytical stream, and the first reaction device is downstream of the first reagent injector and of the sample introduction means; and in that the pumping system comprises a flow control module adapted and configured to maintain a constant flow rate of the analytical stream at the analyte detector, comprising: - a transport medium flow sensor; - a transport medium flow rate adjuster; and - a controller arranged to adjust the adjuster to control the flow of transport medium to compensate for the sample and the reagent introduced into the analytical stream. - a transport medium flow sensor; - a transport medium flow rate adjuster; and - a controller arranged to adjust the adjuster to control the flow of transport medium to compensate for the sample and the reagent introduced into the analytical stream.