<p>A portable system for real time detection of the presence of an infectious agent in a biological sample employs a reagent which detects the presence of a specific infectious agent in the sample, and emits a detectable signal when the reagent reacts with the sample and detects the presence of the infectious agent. A test cartridge has a reaction chamber for receiving the sample and the reagent. The reaction chamber has a predetermined internal geometry and at least one inner surface. Introducing the sample and the reagent into the test cartridge mixes the sample and the reagent. A testing unit receives the test cartridge, and includes a sensor for detecting an emitted detectable signal. The detection of the emitted detectable signal is indicative of the presence of the infectious agent in the sample.</p>