Abstract: A light detection device for alerting an external monitoring system is disclosed herein. In an example, a photosensor apparatus is configured to use one or more photosensors to detect when light is emitted from an indicator lamp of a laboratory instrument. An output from the photosensor(s) is configured to cause a change in a relay switch, which sends a signal to a processor of a system monitor, which may be communicatively coupled to a network. After receiving a signal, the processor is configured to cause the system monitor to generate an alert or alarm indicative that at least one platelet sample within the laboratory instrument has tested positive for bacteria. The system monitor may display the alert or alarm via a user interface and/or may transmit one or more messages to client devices indicative of the light illumination.