A minimally invasive dried blood spot biomarker test for the detection of Alzheimer's disease pathology
Huber et al.
The finding, in our words
The study found that capillary dried plasma spots correlated strongly with venous plasma for detecting the Alzheimer's disease biomarker p-tau217. This suggests that microsampling offers a viable, minimally invasive alternative to venipuncture for screening and monitoring Alzheimer's disease pathology.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
Capillary dried blood spots, after haematocrit-dependent conversion, showed good agreement with plasma for 25-hydroxyvitamin D quantification, with 90 per cent of results within 20 per cent of plasma and substantial to almost perfect agreement in status classification, supporting reliable home self-collection for large-scale vitamin D monitoring.
Capillary finger-stick dried blood spots demonstrated strong analytical agreement with venous serum for prostate-specific antigen (R² = 0.987) and remained stable for 31 days across a wide temperature range. This less invasive microsampling approach enables at-home self-collection, supporting decentralised screening and tele-diagnostics for prostate cancer.
ALAS2 and CA1 mRNA were reliably quantified from venous-cellulose, capillary-cellulose and Tasso-M20 dried blood spots with strong linear agreement (r ≥ 0.96) and no bias for ALAS2. CA1 showed modest proportional bias of 9-22% only when Tasso-M20 was compared with cellulose cards in the rEPO cohort, but no significant differences in relative expression across matrices were observed at any timepoint. These findings support decentralised capillary sampling for longitudinal anti-doping monitoring.
Older adults achieved 98% adherence when self-collecting dried blood spots at home for inflammatory markers, with 97% of samples yielding valid results. Test-retest reliability was good (ICCs 0.70–0.76) and correlation with venous blood was strong (r=0.60–0.99), demonstrating that remote capillary sampling is a feasible and valid method for decentralised assessment of inflammation in older adults.
The study demonstrated that qPCR-based epigenetic immune cell counting from capillary dried blood spots agreed with venous blood and conventional flow cytometry in healthy donors, and then identified lymphopenia, neutrophilia and a lowered lymphocyte-to-neutrophil ratio in 103 COVID-19 patients versus 113 healthy controls, with naive B cell frequency tracking disease severity, suggesting that filter-paper blood collection could enable remote immune monitoring in home-isolated patients.