GFAP and Alzheimer disease: In a study tracking cognitively unimpaired older adults over 12 months, plasma GFAP levels combined with other AD risk factors (age, sex, and APOE ε4 status) showed the highest accuracy in predicting brain amyloidosis compared to other blood-based biomarkers such as total-Tau, p-Tau 181, p-Tau 231, and NFL [32].