This disclosure is directed to kits and methods for extracting a target analyte from a biological fluid in real time. The biological fluid, therefore, does not need to be stored or shipped/delivered. Isolating the target analyte in real-time allows for on-the-spot processing with minimal, if any, down time between collection and testing. Furthermore, isolating in real time may also allow for the biological fluid to be extracted, processed, and returned—similar to that of dialysis—to permit for more volume to be processed and tested. In one aspect, an inner surface of a conduit may include a coating having a high affinity for the target analyte. The conduit may also include features which create turbulent flow to permit all portions of the biological fluid to come into contact with the coating. In another aspect, a capture chip is used to isolate the target analyte from the biological fluid.
