An In-Vitro Test for Alzheimer’s Disease?
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The U.S. Food and Drug Administration recently approved using the first in-vitro test for the early detection of Alzheimer’s disease. This is one more step in the decades-long search for a quicker and more accurate way to diagnose the progressive brain disorder that causes problems with memory, thinking, and behavior.
The move, however, is not a silver bullet solution to a medical puzzle that has confounded researchers.
Lumipulse, as the test is called by Fujirebio Diagnostics, measures the telltale amyloid plaques associated with the disease. Specifically, it quantifies the ratio of two specific beta-amyloid proteins in the cerebrospinal fluid (dubbed 40 and 42), which can form plaques when they accumulate in the brain.
“This is one more tool for us to use, another way of analyzing what we may already suspect,” says Barry Baumel, M.D., a neurologist with the University of Miami Health System. “But it is not a stand-alone test.”
Dr. Baumel points out that physicians have been able to measure amyloid proteins in cerebrospinal fluid for years, but the testing has not always been covered by insurance.
A nod from the FDA “may obligate insurers to pay.”
Also, this new test will likely allow patients to skip positron emission tomography (PET) scans, which are an expensive and time-consuming method of detecting protein clumps. (Some patients also prefer to avoid the radiation risk of a scan.)
Lumipulse is not without its risks, Dr. Baumel adds. Though considered as accurate as a PET scan, there is the possibility of a false negative or a false positive. If used as the only diagnostic method, it could lead to either a delay in treatment or unnecessary treatment. This is why Dr. Baumel says the spinal test is not a stand-alone test but one of several diagnostics that helps the clinician identify and treat the disease.
There are several ways to diagnose Alzheimer’s.
Currently, physicians use cognitive, psychological, and physical exams, aided by a PET or MRI scan. (An MRI is useful in finding brain atrophy.) But researchers have long held out hope for developing an accurate, quick, and non-invasive test that spots the debilitating disorder early — a blood test.
“We’re looking for a simpler way of diagnosing Alzheimer’s,” Dr. Baumel says. “Finding one would help us prescribe targeted therapies more quickly.”
Several blood tests are currently in the clinical trial pipeline. A few show promise and would be a much-needed leap for disease detection. But finding one that checks off all the requirements has proven elusive. That’s because the blood-brain barrier makes detecting Alzheimer’s biomarkers more challenging.
“Other organs deposit substances [that indicate disease or infection] straight into the blood,” Dr. Baumel explains. “It doesn’t happen that way with the brain.”
Because changes in the brain can begin years before first symptoms appear, timely detection is important in a disease that’s proven to be particularly difficult to manage. There is no known cure for Alzheimer’s, and the efficacy of treatments — slowing and managing symptoms — varies.
It is estimated that 50 million people around the world suffer from the disease, 6 million of those in the U.S. As the population ages, that number is expected to nearly triple to 14 million Americans by 2060. One in three seniors dies of Alzheimer’s or another dementia, which means that it kills more than breast cancer and prostate cancer combined.
Ana Veciana-Suarez, Guest Columnist
Ana is a regular contributor to the University of Miami Health System. She is a renowned journalist and author, who has worked at The Miami Herald, The Miami News, and The Palm Beach Post. Visit her website at anavecianasuarez.com or follow @AnaVeciana on Twitter.