Imagine catching the signs of Alzheimer’s before memory loss even begins. Scientists at the Keck School of Medicine of USC have found that future to be closer than we think. The research team has developed a new 5-in-1 blood test that aims to detect early-stage Alzheimer’s disease, years before clinical symptoms emerge.
The test works by identifying biological warning signs in the blood (or biomarkers) that are linked to the earliest changes in the brain caused by Alzheimer’s.
Why early detection matters
Alzheimer’s disease is a progressive neurodegenerative disorder, that often begins silently. By the time noticeable symptoms like confusion or memory loss arise, irreversible brain damage has already occurred.
Current diagnostic tools, such as PET scans or spinal taps, are expensive and invasive. Worse still, they are usually only used after symptoms have appeared and the patient presents to their doctor.
This means we are losing crucial time. Earlier detection opens the door to timely intervention. This includes drugs, in combination with lifestyle and risk factor modifications.
This is particularly relevant with the emergence of new treatments such as lecanemab and donanemab, which are most effective when started in the early stages of the disease.
The Science Behind the 5-in-1 5ADCSI Test
What sets this blood test apart is its multi-marker approach. Instead of relying on a single indicator, it looks at five key protein biomarkers in the blood:
Aβ42 and Aβ40: Proteins that form the plaques seen in Alzheimer’s
Total tau and phosphorylated tau (p-tau217): Associated with AD pathology
NfL (neurofilament light chain): A marker of nerve cell damage
These proteins are measured using ultrasensitive laboratory techniques, the xMAP® technology. This method uses microscopic, colour-coded beads coated with antibodies. These antibodies are designed to latch onto the identified biomarkers in the blood.
When a blood sample is introduced, the targeted biomarkers bind to the beads, which then emit fluorescent signals. Advanced imaging tools are used to detect these signals and quantify the presence of each protein.
With the test built, researchers trialled it on 63 individuals divided into three groups: 11 patients with Alzheimer’s disease, 17 with mild cognitive impairment (MCI), and 35 healthy participants. The results followed a clear pattern – those with Alzheimer’s had the highest biomarker levels, followed by those with MCI. Among all five markers, p217Tau stood out as showing the strongest association with Alzheimer’s pathology.
To further validate the test, the team compared blood results with samples taken from cerebrospinal fluid (CSF) – the more traditional, but invasive, method of measuring these proteins. Despite CSF generally containing higher protein concentrations, the study found moderate to strong correlations between blood and CSF results.
This suggests the blood test is sensitive enough to pick up early Alzheimer’s changes, without the need for a lumbar puncture.
What Makes the 5ADCSI Test Different
While several blood-based tests for Alzheimer’s already exist, most come with significant drawbacks. Many are costly, rely on highly specialised equipment, and focus on only one or two biomarkers.
In contrast, the 5ADCSI test monitors five key biomarkers simultaneously using xMAP® technology – a platform already in use across many hospitals and research labs worldwide. This means testing can be more efficiently, and at a relatively low cost.
Affordability is not just a bonus – it could even transform Alzheimer’s screening. If rolled out more widely, 5ADCSI could one day function like routine tests for cholesterol or blood sugar, helping clinicians spot patients at risk long before symptoms emerge.
As research into anti-Alzheimer’s drugs such continues, the need for earlier and simpler diagnostic tools grows. Tools like the 5ADCSI test may be key to shifting Alzheimer’s care from reaction to proactive prevention, giving patients a chance to intervene while there is still time to preserve brain function.
