Brain HealthBlood Biomarker Disclosure Doubles Alzheimer Diagnostic Certainty in Randomized Trial
A randomized trial at a Spanish memory clinic tested whether revealing blood-based Alzheimer biomarkers — specifically plasma phosphorylated tau 217 (p-tau217) and neurofilament light chain (NfL) — earlier in the diagnostic process improves outcomes. Among 220 patients with subjective cognitive decline, mild cognitive impairment, or mild dementia, those who received their results at 3 months were dramatically more likely to achieve a high-confidence etiologic diagnosis than those who waited until 9 months (50% vs. 4.6%). Earlier disclosure also led to more patients starting Alzheimer treatment sooner, fewer unnecessary follow-up neuropsychological tests, and more appropriate referrals back to primary care. Critically, receiving results early did not increase anxiety, depression, or perceived stress. The findings make a strong case for integrating blood-based biomarkers into routine memory clinic evaluations.
