The risks associated with making decisions based on poor-quality information are quite high. Consequently, the management of information quality (IQ) and the quality of associated information management processes has become critical for healthcare organizations. An important first step in managing information quality is the ability to measure the risk of information products based on the quality of the source data and associated processes used to produce the information outputs. This paper suggests a methodology to calculate two information quality characteristics-preciseness and completeness - for the HIS database. Four quantitative indicators are introduced to assess the risk of medical information quality. The methodology is illustrated through a medical domain: infection control. The results show the methodology was effective to detection and aversion of risk factors.