Few illnesses instill as much fear as Alzheimer’s, a fatal neurodegenerative disease that destroys memory and identity. The dread is compounded by the uncertainty that often surrounds the diagnosis of the most common form of dementia.
Brain autopsies remain the only way to know for sure whether someone had the disease, which the Centers for Disease Control and Prevention estimates affects 6.5 million people in the United States. Over the past several years, sophisticated tests such as spinal taps and specialized PET scans have become available — but they are invasive and costly and not routinely used.
As a result, Alzheimer’s is frequently misdiagnosed, especially in the early stages. Other illnesses, including depression, can have similar symptoms and require other treatments.
But simple blood tests designed to help doctors diagnose Alzheimer’s now are on the market. More are on the way. The tests are seen as an important scientific advance, but have ignited debate about how and when they should be used.
Some experts say much more research is needed before the new tests can be widely deployed, especially in primary-care settings. Others say there already is sufficient information on the accuracy of some tests. All agree that no single test is perfect and physicians still should perform a complete clinical assessment.
Widespread use of the tests may be some time off in the future — after insurance coverage improves and even more accurate next-generation tests become available. For now, none is covered by Medicare, and private insurance coverage is patchy.