The doctor should order a panel of bloodwork including basic metabolic labs and vitamin levels (especially B12, folate, and B6), check thyroid and adrenal function, screen for depression, and get brain imaging — an MRI or CT scan. If reversible causes of symptoms, like buildup of fluid in the brain, are ruled out and neurodegeneration is suspected, neurocognitive testing combined with a cerebrospinal fluid test, amyloid PET scan, or one of the newer FDA-approved blood tests can be used to confirm or rule out Alzheimer’s.