Two blood tests that flag Alzheimer's disease pathology work in people with Down syndrome, according to a USC-led study published in the journal Communications Medicine. Researchers at the USC Epstein Family Alzheimer's Therapeutic Research Institute evaluated Lumipulse G p-tau217 and PrecivityAD2, and found both effective at detecting Alzheimer's pathology in this group. It is the first study to enroll participants with Down syndrome to test these assays.
The gap this fills is a striking one. People with Down syndrome develop Alzheimer's at dramatically higher rates than the general population, yet the Lumipulse G p-tau217/beta-Amyloid 1-42 test the FDA approved in 2025 to aid Alzheimer's diagnosis is not available to them, simply because it had never been studied in that population. Blood tests matter here because the alternatives - PET brain scans and spinal taps - are more invasive and harder to access, barriers that weigh especially heavily on patients who may struggle with lengthy or uncomfortable procedures.
Earlier detection also has practical stakes. Drugs designed to slow Alzheimer's progression have a better chance of helping when the disease is caught at an early stage, so a simple blood draw that identifies underlying pathology could change when treatment conversations begin. The researchers framed their work as a step toward making these tests available to people with Down syndrome, and encouraged clinicians to use them to help families understand what may be driving the symptoms they are seeing at home.
PrecivityAD2 is already widely used in research settings, while the Lumipulse test carries FDA clearance for the broader population. Extending that clearance and routine clinical use to people with Down syndrome will depend on further validation, but this study establishes that the biology the tests measure holds up in a group that has long been left out of Alzheimer's diagnostic research.