Abstract: A sample analyzer incorporates a sensor unit for providing a desired analysis of a sample. The analyzer includes a first body portion having a sensor surface (of the sensor unit) to which a sample is applied for effecting the analysis, a second body portion which is openable and closable together with said first body portion, a chamber incorporating the sensor surface when the first and second body portions are in the closed position, at least one reservoir for holding a treatment liquid and is capable of communicating with the chamber and providing a supply of treatment liquid to the chamber when the body portions are closed.