Researchers at the Keck School of Medicine of USC have developed a new, low-cost blood test that can detect early signs of Alzheimer’s disease by measuring key protein biomarkers. Named the Penta-Plex Alzheimer’s Disease Capture Sandwich Immunoassay (5ADCSI), this test is more advanced than current options—it detects five biomarkers at once using widely available lab equipment.
Study Published in Journal of Alzheimer’s Disease
A recent proof-of-concept study, published in the Journal of Alzheimer’s Disease, highlights the potential of 5ADCSI in transforming early diagnosis. Existing blood tests often rely on expensive tools and detect only a limited number of biomarkers. In contrast, 5ADCSI runs on xMAP technology from Luminex, already used in many hospitals and laboratories.
“The biggest advantage is affordability and accessibility,” said Dr. Ebrahim Zandi, lead researcher and associate professor of molecular microbiology and immunology. “Many labs already have the necessary equipment, making this test easier to implement on a wide scale.”
Biomarkers Detect Disease Before Symptoms Begin
Alzheimer’s disease develops gradually over 10 to 20 years as amyloid and tau proteins accumulate in the brain and bloodstream. Zandi emphasized that detecting these markers early could allow timely intervention through medication or lifestyle changes.
Creating the 5ADCSI Test
To build the test, researchers selected five biomarkers strongly associated with Alzheimer’s: Aβ40, Aβ42, phosphorylated tau (p217Tau), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP). Using xMAP technology, they designed color-coded beads coated with antibodies to capture these biomarkers from blood samples.
Testing involved 63 participants—11 with Alzheimer’s, 17 with mild cognitive impairment, and 35 healthy individuals. The test showed the highest biomarker levels in Alzheimer’s patients, followed by those with cognitive decline. Notably, p217Tau displayed the strongest link to the disease.
Comparable to Cerebrospinal Fluid Tests
As reported by medicalxpress, researchers also used the 5ADCSI method to analyze cerebrospinal fluid (CSF), which contains more detectable Alzheimer’s proteins but is difficult to collect. They found strong correlations between blood and CSF results, reinforcing the blood test’s sensitivity and reliability.
Towards Clinical Use and Broader Screening
Initially developed to support cognitive aging research, 5ADCSI is now progressing toward clinical application. The team plans to validate its accuracy in a larger patient group across various stages of Alzheimer’s.
Zandi hopes to integrate this test with genetic screening for APOE4, a known Alzheimer’s risk gene. This combination could form the basis of a comprehensive brain health risk assessment, bringing personalized, preventive care within reach—even in resource-limited settings.