Friday, February 01, 2008

Genetic tests and clinical utility

There was a story on NPR's Talk of the Nation earlier this week (listen here) about the array of genetic tests that are now available to you, the consumer. The news hook was a new blood test that researchers claim can define individuals' likelihood to develop Alzheimer disease. Like many other such tests, this one doesn't yield a yes/no answer: it identifies an increased propensity to develop the condition. It can't say for sure whether a person will in fact get Alzheimer disease, or, if she does, what the course of the illness is likely to be. But, for many people, the trouble is not just the certainty of the diagnosis or the accuracy of the prediction.

For some conditions, like Alzheimer's and Huntington's, treatment is limited and cures have not yet been found ... so there isn't anything that a person might do differently to reduce the risk of getting sick. The clinical utility of testing in these situations is limited: the results of the test will not change the medical management of the patient. Some people want such information to help them plan for their own futures and those of their families; others don't want to know and might see such unwanted information as burdensome.

Lots of questions here. Would you want to know? What is the value of information in this situation, and are all reasons for testing equally deserving of respect? Should such tests be available in direct-to-consumer form, without medical direction or involvement--and does it matter if the reason people pursue testing "off the books" is to prevent their insurance company from finding out that they're at increased risk? Should counseling be mandatory, or is that too much paternalism?

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