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By: George Citroner
Alzheimer’s disease is a looming threat as we age. The most common cause of dementia, it afflicts roughly 1 in 9 people over 65—with women making up a full two-thirds of cases. For years, Alzheimer’s could only be definitively diagnosed after death through autopsy.
But promising new blood tests offer hope that doctors can determine who is most at risk and gain time to use revolutionary new treatments that could slow the disease’s progression. However, it’s important to remember that these tests aren’t yet approved by the U.S. Food and Drug Administration (FDA) and don’t actually diagnose the disease, only risk.
Alzheimer’s Blood Tests Are Less Invasive
While PET scans and cerebrospinal fluid-based (CSF) tests are currently the standard for diagnosing Alzheimer’s, they’re expensive. The average cost of a PET scan in the United States is around $6,000, and a spinal tap procedure is about $1,000.
But many doctors expect less invasive, cheaper blood tests to play a major role soon in diagnosis and disease management.
Blood-based biomarker testing is a promising alternative, Dr. Anita Szerszen, director of inpatient geriatrics at Northwell Staten Island University Hospital in New York, told The Epoch Times. “The specific group of blood biomarkers called phosphorylated tau proteins are so far the best possible candidates for identifying early changes in the brain that predict Alzheimer’s before symptoms such as memory loss emerge,” she added.
Also, two key developments may increase medicine’s focus on blood-based testing.
The FDA recently approved Biogen’s Aduhelm and Eisai’s Leqembi, both drugs designed to slow Alzheimer’s progression. Blood-based tests may be beneficial because doctors will have a quicker way to tell who should be prescribed these medications without scheduling PET scans and spinal taps for all suspected cases, spiking costs and slowing diagnosis.
Blood Tests Already Available
Several blood tests exist for early Alzheimer’s detection, with varying accuracy based on test type and measured biomarkers. While Dr. Szerszen said she would not recommend testing without discussing the implications and their interpretation with a specialist, researchers have generally found them effective at identifying early disease indicators. Available tests include the following:
Protein test: The neurofilament light chain (NfL) test measures NfL protein levels, a neurodegenerative disease biomarker. Elevated levels of NfL have been found to correspond with the onset and progression of neurological diseases, including Alzheimer’s. However, the test isn’t specific to Alzheimer’s, and NfL protein is only considered evidence of neurodegenerative disease in general.
Genetic test: The ApoE gene test looks for specific variants of a gene called ApoE that are associated with an increased risk of developing Alzheimer’s disease. The ApoE gene test reveals lifetime Alzheimer’s risk but cannot predict the disease.
Plasma ratio test: In a recent study published in Neurology, one blood test detecting amyloid plaque buildup in the brain by measuring proteins in blood was nearly 90 percent accurate at predicting Alzheimer’s onset within four years. The commercial version of this test is called PrecivityAD.
The First Alzheimer’s Blood Test for Sale Direct-to-Consumer
Quest Diagnostics recently announced the first direct-to-consumer Alzheimer’s risk test: AD-Detect. It is based on the same technology as the plasma ratio test.
“Blood tests like AD-Detect hold incredible potential to make Alzheimer’s disease risk assessment both accessible and convenient,” Dr. Michael K. Racke, medical director of Neurology at Quest Diagnostics, said in a press statement.
