Diagnosing Alzheimer’s Disease is a difficult procedure, but the Food and Drug Administration recently approved a primary care blood test for those 55 and older that may help simplify the process.
KERA’s Sam Baker talked about it with Dr. Brendan Kelley. Dr. Kelley leads UT Southwestern Medical Center's clinical trials on dementia. He's also a Professor and Clinical Vice Chair of Neurology at UTSW.
Dr. Kelley: The blood tests that have recently been approved by the FDA can be very helpful in evaluating patients that are having cognitive decline or who are experiencing dementia, but they in and of themselves may not be sufficient to establish a diagnosis of Alzheimer's disease.
Baker: So, what's the real benefit of the test?
Dr. Kelley: It's less invasive than other modalities that we might use to evaluate Alzheimer's disease, such as collecting spinal fluid.
Now, if we were to consider using one of these new therapies that targets amyloid deposited in the brain, we would want to confirm that amyloid was in fact present using a more advanced technology like a PET scan . A blood test can be very useful to determine where a PET scan may be indicated.
In other words, if that blood test were negative, the likelihood that the PET scans would demonstrate significant levels of amyloid in the brain is relatively low.
If the blood tests were positive, that would confirm that it's very likely that the amyloid PET scan is going to be positive. So, it can be used as a very powerful screening tool.
Baker: Do you seek a test like this when someone has had some type of confirmation of dementia or Alzheimer's disease, or does a person who thinks they been getting a little forgetful lately, should get the test and have a look-see?
Dr. Kelley: Let's say that person does not have any cognitive symptoms or even any concerns about their memory at this time, and perhaps that person has a strong family history of dementia or Alzheimer's disease, we would recommend not to use this as a screening test.
Meaning, if that person who was cognitively normal had an abnormal blood test, there's not any FDA approved medication that would be indicated. To try to address that.
The situation changes if a person is having memory concerns or they or their family members are expressing some concerns about forgetfulness and perhaps they bring these up with their physician who does some cognitive testing and perhaps, they find some mild cognitive difficulties.
In that person, a blood test like this could be a very powerful tool to figure out whether those mild cognitive symptoms could represent early signs of Alzheimer's disease.
Baker: I've done interviews with people off and on about dementia and Alzheimer's. Most of those are always about trying to figure out what this disease is, and how do we proceed with it. But somehow it seems in recent years we've made enormous strides with it?
Dr. Kelley: That's absolutely accurate.
If you were to look at Alzheimer's research, from the bird's eye view of it, you would find two major thrusts of research. One is the development of more accurate biomarkers or ways to detect the disease and refining these biomarkers so that they could detect the diseases at the earliest possible stage.
The other important thrust has really been in refining our biochemical and biological understanding of the disease and developing new therapies or new treatments interventions that can target the pathology of Alzheimer's disease and hopefully slow or even stop it altogether.
And so, in the past two or three years, we've seen the FDA approve the first new medications to treat Alzheimer's Disease in over 20 years. That's very exciting in the field.
RESOURCES:
FDA Clears First Blood Test Used in Diagnosing Alzheimer’s Disease
