Finger prick test detects blood-based biomarkers of Alzheimer’s disease

Key takeaways:

• Researchers collected venous and finger prick blood samples from memory clinic patients and tested for biomarkers of Alzheimer’s disease.
• Several biomarkers were detected in the finger prick samples.

A finger prick test measured blood-based biomarkers of Alzheimer’s disease and has potential to increase accessibility of testing, according to research at the Alzheimer’s Association International Conference.

“Currently, use of Alzheimer’s blood tests is limited by the need to visit a clinic, administration by trained personnel, and strict time-limited and temperature-dependent delivery and storage procedures,” Hanna Huber, PhD, of the Institute of Neuroscience and Physiology at the University of Gothenburg in Sweden, said in a related release.

Huber and colleagues initiated a pilot study to determine the capability of capillary dry blood spot (DBS) and venous DBS to measure specific biomarkers of neurodegeneration: neurofilament light (NfL), glial fibrillary acidic protein (GFAP) and phosphorylated tau (p-tau181 and p-tau217).

They collected venous and finger prick blood samples, EDTA plasma and neuropsychological measures from 43 memory clinic participants at ACE Alzheimer Center Barcelona and also examined cerebrospinal fluid biomarkers in 23 of those patients.

Researchers prepared 65 L of venous and capillary blood on DBS cards (Noviplex), which were shipped overnight without temperature control or cooling, to Gothenburg, Sweden. Dried blood samples were extracted from the cards, and NfL, GFAP and p-tau181 were measured.

Huber and colleagues used Pearson correlation for analysis of the DBS samples and EDTA plasma.

According to results, capillary DBS GFAP (r = 0.6773; P < .0001) and NfL levels (r = 0.4593; P = .0022) correlated with their counterparts in EDTA plasma. Similarly, venous DBS GFAP (r = 0.7624; P < .0001), NfL (r = 0.6798; P < .0001) and p-tau181 (r = 0.577; P < .0004) significantly correlated with EDTA plasma.

Additionally, both capillary and venous DBS GFAP correlated with amyloid status (r = 0.4305/r = 0.4223; P < .05) and venous DBS NfL and p-tau181 correlated with Mini-Mental State Examination and Clinical Dementia Rating assessments, as well as amyloid (all P < .05).

“A method that allows blood collection at home and that is simple enough to be performed independently, or by caregivers, would increase accessibility of these tests,” Huber said in the release. “It would result in improved early diagnosis and better monitoring of patients considered ‘at risk’ or those who are receiving approved therapies.”

Reference:

• Simple finger prick test exemplifies advances in Alzheimer’s disease blood tests. https://aaic.alz.org/releases_2023/finger-prick-blood-test-alzheimers-disease.asp. Published July 19, 2023. Accessed July 19, 2023.