There is provided a medical device comprising a skin attachment surface and an evaporation layer, and at least one hollow microneedle extending from the skin attachment surface, the device further comprising a flow channel, an analysis unit and an evaporation layer, where the microneedle is connected to a flow channel, where the flow channel is arranged to transport fluid from the tip of the needle to the evaporation layer, the flow channel being connected to the analysis unit for analysing the fluid, where the flow channel is connected to the evaporation layer such that the flow channel can release fluid into the evaporation layer where at least a part of the fluid evaporates.