Diagnostic Test Available for Clinical Trials, not Clinical Practice

I was excited when I first read about the P-Tau 231 Test developed by Applied NeuroSolutions. The test analyzes cerebrospinal fluid for tau, a protein that accumulates in the brains of those with Alzheimer's. Twenty-one research articles have been published on its utility, claiming that the test has 85-95% sensitivity and specificity in distinguishing those with Alzheimer's from those with other types of dementia and those with other chronic conditions.

When I read this, my first thought was, "Great! When will it be available to physicians so they can better diagnose Alzheimer's?" But then I read that the test won't be available to practicing physicians -- at least not yet. Instead, the company is marketing the test to pharmaceutical companies and others conducting clinical trials so they can better classify participants in their studies.

I'm all for conducting quality research, but if a test is good enough for Alzheimer's research, why isn't is good enough for clinical practice? According to its website, Applied NeuroSolutions is working on developing a blood test (as opposed to a cerebrospinal fluid test) that will be easier to use and less expensive. Maybe the company is planning on making that one available to practicing physicians.

Still, there are a lot more people with Alzheimer's-like symptoms who aren't participating in clinical trials than there are clinical trial participants. In other words, if the test is so well-established, why not make it available for both research and practice? It would certainly help more people that way.

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