Abstract: A method for detecting the presence of blood in a dialysate solution is disclosed. The method provides for certain measurement of light intensity passing through solutions both before and during the dialysis session. Before dialysis is commenced, measurements are made of the intensity of light passing through a chamber containing a control dialysate solution that is free of blood. The light source is a first condition. The light source's state is changed from a first condition to a second condition different from the first condition. Next, a second measurement of the intensity of light is made. The first and second measurements are stored. During dialysis, the method continues with the following steps: conducting a third measurement of the intensity of light of the light source that passes though the chamber, the chamber containing dialysate solution that may contain the patient's blood, with the light source in the first condition.

Abstract: A method and apparatus for optically communicating data between a stationary member and a rotating member, wherein a transmitter, disposed on the rotating member, is provided for transmitting an optical beam therefrom at an angle with respect to the rotating member the angle being fixed during transmission of the optical beam, a receiver, disposed on the stationary member, is provided for receiving the optical beam, and a reflector, disposed on the stationary member, is provided for reflecting the optical beam to the receiver at all times when the optical beam is incident on the reflector.