The three main aspects of analytical quality are 'goals for analytical quality', 'creation of analytical quality', and 'control of analytical quality'. In the NORDKEM-project 'medical need for quality specifications within laboratory medicine' the aspects of analytical quality are combined. The aims is to make an appraisal of the different approaches to goal setting, and to develop a practical procedure for assessing analytical quality requirements. The goals are used to define which demands should be met by the process of establishing and maintaining the quality, and for design of internal as well as external quality assurance procedures. The project is an umbrella project with three main subprojects and several satellite projects. In this presentation a model for evaluation of influence of analytical bias and imprecision on the outcome from a diagnostic classification based on bimodal distribution is described.