Predictive testing and population screening

Abstract

Historically, medicine has focused on the treatment of disease. The aims were to diagnose the clinical problem, cure if possible and alleviate suffering where cure was not possible. While these still remain fundamental aims in health care, there has been an increasing focus on the prevention of disease and disability, including identification of syndromes or disease in the preclinical stages, and at-risk individuals or groups, with early intervention to reduce morbidity and mortality. There are several reasons for this shift in focus. Conceptually, if the goal of medicine is to relieve suffering from disease then prevention of disease, or at least long-term complications of disease, must be a key objective. Increasing medical knowledge and technology now provides the means to identify early pointers to future disease, including identification of genetic predispositions and other risk factors and better imaging techniques for early diagnosis, for a wide range of conditions. For health policy-makers, the potential economic efficiency gained by preventing disease and reducing the cost of treatment is also a contributing factor. However, strategies for preventing disease engender their own potential harms and there has been debate in both the academic and public arena about the ethical aspects of such programmes. In this Five-Minute Focus (FMF), the ethical issues raised by the strategy of predictive testing and population screening for disease are considered. Screening can be broadly divided into whole population screening and screening of at-risk groups. Further, categorization according to the nature of the condition being screened for or the screening subjects can be made and includes the overlapping categories listed below. Predictive testing, for example genetic testing for Huntington's Disease, focuses on individuals and includes testing for conditions for which there may be no effective treatment. Screening for conditions that only affect the person being screened. For example, cervical cytology screening, mammography screening, cardiovascular risk assessment; screening for conditions which can be transmitted to others, for example, HIV testing or screening for TB; screening for genetically-determined conditions which have implications for other family members; screening those who are unable to give consent to screening, for example neonatal screening for metabolic diseases; screening embryos and fetuses. Antenatal and pre-implantation screening are not considered here as this merits more detailed discussion in a future FMF.