Costeffectiveness of diagnostic tests.

We review the principles underlying cost-effectiveness analysis of diagnostic tests and procedures. We use two clinical examples, diagnostic testing for early multiple sclerosis and for Helicobacter pylori to illustrate the methods of analysis and to show how the results can be useful for physicians or payers of health services in making decisions about provision and use of diagnostic services. Economic assessments of diagnostic tests are inherently more difficult than assessments of therapeutic interventions, mainly because of uncertainty about the relation between diagnosis and end results (outcomes) of care. Nonetheless, because of the increasing importance of diagnostic technology in medicine and healthcare, only with such assessments will the most value be gained from restricted medical resources.