Finger-prick blood test for Alzheimer disease

Around 6 million people in the U.S. currently live with Alzheimer's disease. By 2050, this figure is projected to increase to almost 13 million.

While there is currently no cure for Alzheimer's, studies show that early diagnosis and intervention are crucial for delaying its onset.

Current diagnostic methods include magnetic resonance imaging (MRI), cognitive tests, and physical exams. However, they have restricted accessibility as they require visiting a clinic with trained personnel and complex delivery and storage procedures for samples.

The accuracy of such tests also varies. A study found that around 25%Trusted Source of patients clinically diagnosed with probable Alzheimer's during their lifetime did not have evidence of Alzheimer's at autopsy.

Research also shows that up to 50%Trusted Source of patients with any form of dementia are not formally diagnosed while alive.

Improving the accuracy and availability of Alzheimer's testing could help physicians diagnose the disease sooner and prescribe interventions to potentially delay disease progression.

Recently, researchers designed a method to analyze finger prick tests for Alzheimer's that can be taken at home without the need for clinician oversight.

Another study found that blood tests can yield over 85% accuracy in detecting Alzheimer's, whereas standard physical examinations deliver accurate diagnoses around 55% of the time.

The findings were presented at the Alzheimer's Association International Conference in Amsterdam, Netherlands, and online.

For the study, the researchers included 77 memory clinic patients in Barcelona, Spain. All participants provided venous and finger prick blood samples as well as neuropsychological measures.

Blood samples were either spotted and dried on 'dry blood spot' (DBS) cards or preserved via an anticoagulant called ethylenediamine tetraacetic acid (EDTA) for overnight shipment to the University of Gothenburg in Sweden.

Whereas EDTA blood samples need to be refrigerated, DBS cards only require shelter from humidity and moisture, making them easier to transport. EDTA samples also require centrifugation—the mechanical separation of fluids according to their density—before they can be examined, whereas DBS does not require this step.

Once in Sweden, the researchers tested the blood samples for Alzheimer's-related biomarkers, including neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and phosphorylated tau.

They noted that Alzheimer's biomarkers were present in all of the blood samples.

This means that Alzheimer's biomarkers can be quantified via finger prick collection and that DBS could help with regular monitoring of patients with suspected neurological conditions.