A therapy system for treating a tissue site with negative-pressure therapy and/or fluid instillation therapy in response to information received from a diagnostic module is disclosed. In some embodiments, the therapy system may include a dressing, a negative-pressure source, a container, and a diagnostic module. The dressing may be adapted to be placed on the tissue site, and the negative-pressure source may be adapted to be fluidly coupled to the dressing. The container may be adapted to be fluidly coupled to the dressing and to the negative-pressure source and to receive fluid from the tissue site. The diagnostic module may be adapted to be exposed to gas associated with the fluid from the tissue site. The diagnostic module may comprise a sensor configured to detect a condition of the tissue site and to generate an output based on the detected condition. The sensor may be configured to detect a volatile organic compound. In some embodiments, the diagnostic module may be positioned on the container.