A spinal fluid tap may be 100% accurate in predicting whether a patient will develop Alzheimer’s disease, according to a study published in Archives of Neurology.

According to the New York Times, until now the presence of the disease could only be confirmed after an autopsy, although it begins ten or more years before symptoms appear. But a simple spinal tap could predict whether someone has the progressive and incurable brain disease and identify them as potential subjects for research into cures. “This is what everyone is looking for, the bull’s-eye of perfect predictive accuracy,” said Dr Steven DeKosky, dean of the University of Virginia medical school.

The news was widely reported in the media and shot to the top of the most-read articles in the Times. The conumdrums of a screening test for Alzheimer’s were clear to everyone. Would healthy people want to know that they have a disease for which there is no cure? How would they react?

For researchers, the benefits are obvious. It would be far more efficient to test potential treatments on people in the initial stage of the disease. In an accompanying editorial, two experts declared that spinal taps may become a routine “screening test to identify clinically healthy individuals at risk”. This would be helpful in developing “early application of treatments to delay onset of symptoms or slow progression of cognitive impairments”.

Bioethicist Jonathan Moreno, of the University of Pennsylvania, pointed out in The New Republic that the existence of an accurate and relatively simple test creates many policy problems. As many as 5.1 million Americans may have Alzheimer’s. How will that affect their health insurance? How will it affect families? Will it lead to suicide or will it encourage people to put their affairs in order? ~ New York Times, Aug 9