New test for Alzheimer’s, non-invasive and FDA-approved, now available in India: Why this helps in tracking early symptoms

What is the new test about?

It’s basically intended to detect Alzheimer’s early as the age of onset is reducing to about 45. It is non-invasive and can help those who have a family history of Alzheimer’s or dementia, experience brain fog, memory lapses, have trouble concentrating and live with risk factors such as diabetes, hypertension, or obesity.

As we know, Alzheimer’s is diagnosed in just about 10 per cent of individuals who have it right now. This FDA-approved test bridges that gap. It’s not a single test. These are multiple sequential tests that give end-to-end clarity for a doctor to arrive at a conclusion as to whether a person is prone to developing Alzheimer’s or not.

Why does the test have various levels?

At first, the person starts with what we call a digital cognitive assessment. This is like a simple quiz that is very user-friendly and takes about 15 to 20 minutes to complete. You can take the test on your personal devices. It consists of some puzzles and games that basically evaluate the various functions of your brain, be it memory, executive function and your behavioural responses. On the basis of this cognitive assessment, you get a brain score, which can indicate whether there is any kind of mild cognitive impairment.

How do you know when to take the test?

It is only to be advised by a physician when they see a patient with some symptoms of cognitive impairment. The quiz or mental cognitive assessment is step one. If the patient’s parameters here are more than the threshold, then a simple blood test is recommended.

The sample is then analysed by a special instrument called the chemiluminescence, which uses antibodies and chemical reactions to generate light, enabling highly sensitive detection and quantification of Alzheimer’s biomarkers like tau and amyloid proteins in blood plasma. The results, often expressed as a ratio of different biomarkers, are used to assess the likelihood of Alzheimer’s disease and differentiate it from other neurological disorders. If your value is more than a particular limit, then that means you might have Alzheimer’s.

Why Alzheimer’s testing takes time

Once tested positive in step 2, another blood sample is sent for a C2 test, which has been developed by a US-based lab. This gives a combined score based on biomarker levels, which is called an Alzheimer’s probability score. This guides sharper diagnosis.

We supplement this with a genetic test, called an APOE genotype test, to ascertain if you are predisposed to developing Alzheimer’s. This is particularly helpful to detect late-onset Alzheimer’s. A confirmatory diagnosis requires multiple reflex testing or sequential testing that the patient has to go through under the guidance of their physician.

What are the advantages of this confirmatory test?

Currently the most common method of diagnosing Alzheimer’s is a very painful spinal tap that basically involves doctors extracting spinal fluid from the spinal canal. No one can get this done routinely and that’s why a lot of people go undiagnosed. Then there are PET scans, which can visualise amyloid plaques and tau tangles. Again, these are not widely accessible.