Taking a count: the evaluation of genetic testing

While some forms of genetic testing have been available for decades, the pr ogress of the Human Genome Project will expand the possibilities for testin g. Evaluation of genetic testing is warranted because health care services have an opportunity cost and thus the benefits of testing must be assessed against the costs. However, genetic testing raises new methodological diffi culties in taking into account the full range of costs, benefits and risks. The conventional approach to evaluating new technologies is to assess thei r benefits in terms of health outcomes only, and to consider the effects on the individuals being tested. Like any test, the product of genetic testin g is information. Any subsequent health outcome gain depends on the effecti veness of any intervention which results from the information. Assessing th e benefits in terms of health outcomes only excludes consideration of any v alue, both positive and negative, attached to information. The special feat ure of genetic testing is that the information obtained has implications fo r family members. This information may have value to relatives individually and may affect family interactions. Information also has value at a social level; it may affect social relationships and interactions. As the possibi lities for genetic testing expand, it is likely that testing programs will be subject to economic evaluation. Until the methods and measures used can validly take this range of effects into account (and into a count of benefi ts), then the results of evaluation studies will be, at best, incomplete an d, at worst, misleading.