Commercial genetic testing has surged in the last few years in response to successfully sequencing the human genome.  Using genomic markers to identify diseases well ahead of any symptoms has enormous appeal, but there are several reasons why employers should be cautious about offering genetic testing as an add-on to their medical benefits offerings. First, molecular biology is very complex. For example, if genetic testing yields a positive result for a gene correlated with a certain condition, it still may not be that meaningful since it can take multiple triggers to initiate a disease.  The testing result only provides a probability based on a current statistical correlation, and that probability can change as the science or as conditions progress — genes placed on a list of markers for a specific condition have been removed from that list just a  few years later as new studies emerge.

Second, the benefits of early detection can be misleading. There is a term in the screening industry called “lead-time bias” which occurs when a disease is detected earlier due to improved technology, but retrospective studies show that early diagnosis did nothing to change the course of the disease.  In other words, five-year survival rates improve, but only because the starting point of the lifespan measurement moved backward to the point of earlier detection.

Third, the psychological effects of a test yielding a high probability can be difficult to live with.  The likelihood of a disease may be high, but the consumer doesn’t know when the disease will manifest (if ever), and if it will be treatable.   The knowledge can be so debilitating that the term “previvor” has emerged to describe someone who’s survived an illness they haven’t even had yet.

Certainly, there are some genes that are so strongly linked to disease manifestation that testing would be beneficial and companies offer counselors to explain the meaning and limitations of the findings, but until the predictive value of genetic testing improves and can demonstrate a positive return on investment (ROI), including these programs in medical benefit packages should be approached with caution.