Blood tests for Alzheimer's show promise but lack FDA approval, with some experts skeptical of their clinical use. Though cheaper and less invasive than PET scans or lumbar punctures, these tests are not yet standardized and cannot diagnose the disease alone. The best biomarker, pTau-217, is emerging, with Precivity's C2N test considered one of the best available. Despite their potential, blood tests are not yet ready to replace more invasive diagnostic methods, and their effectiveness in diverse populations remains unclear.