The ability to diagnose disease is running ahead of the ability to treat disease, and there has been a fair amount of discussion of late about the use of diagnostics in currently untreatable diseases.

Nevertheless, there are clearly some diseases for which the market demands diagnostics, even without treatment. Alzheimer's disease (AD) is a case in point. Patients and their families already spend $1,500-$3,000 in an effort to diagnose the disease in patients who exhibit signs of dementia, according to Athena Neurosciences Inc., which has just introduced the first specific tests to aid neurologists in the diagnosis of AD.