The role of test accuracy in predicting acceptance of genetic susceptibility testing for Alzheimer's disease.

A survey questionnaire regarding perceptions of risk and genetic susceptibility to Alzheimer's disease (AD) was completed by 518 offspring of AD cases from families with multiple affected, ascertained as part of a genetic linkage study of late onset AD. The questionnaire focused on respondents' perceptions of their own risk for AD as well as on the properties of real and hypothetical susceptibility tests, including error rates for false-positive and false-negative test results. Our findings showed that about 20% of the sample would refuse a susceptibility test with zero error rates, about 40% would accept tests with very high error rates in both directions, and the remainder would exercise some discrimination. Acceptance of high test error rates was significantly associated with male gender, low education, and high perceived lifetime risk of AD. In a previous paper related to this work, we showed that physicians caring for these families exercised much more discrimination in judging the acceptability of genetic tests they would offer to these same respondents. The findings show that there is a pressing need to educate the public, particularly those with relatives affected by a complex disease, to expect standards of accuracy for genetic tests comparable to those that prevail in other diagnostic and prognostic testing efforts in the broad field of clinical medicine.