The rapid monitoring of cleaning performance is done by detection of ATP (Adenosine Triphosphate) on critical surfaces. ATP is a biochemical present in all living organisms and biological residues. If ATP is detected on a cleaned surface, it means the cleaning was not effective and the surface is a hazard for spread of microorganisms. The ATP method is quick, simple and easy to do and objective. The result is given in RLU (relative light units) and interpreted automatically by the instrument (Pass/Caution/Fail), so the operator can take appropriate action based on the result. Results are stored in the instrument memory and can be uploaded to a computer for further analysis and data management.