Getting a Diagnosis
How doctors evaluate memory problems—cognitive tests, blood tests, brain scans and the new Alzheimer's blood tests—and how to prepare.
Last reviewed: October 2026
If you're worried about memory changes in yourself or someone you love, getting evaluated is the most important next step. A diagnosis can reveal a treatable cause, open the door to treatments that work best early, and give time to plan. Diagnosis has improved dramatically in the last few years, including new blood tests for Alzheimer's.
Where to start
Start with a primary care doctor. Many memory evaluations begin there, and Medicare covers a yearly wellness visit that includes a check for cognitive impairment. Depending on what's found, you may be referred to a specialist:
- Neurologist – brain and nervous system
- Geriatrician – care of older adults
- Geriatric psychiatrist – mood and thinking in older adults
- Neuropsychologist – detailed thinking tests
- Memory clinic or Alzheimer's center – teams that specialize in diagnosis
How to prepare
- Write down the changes you've noticed, with examples and when they began.
- Bring all medicines, including over-the-counter drugs, vitamins and supplements.
- Bring a family member or close friend—they can describe changes and help remember what the doctor says.
- Note family history of dementia or other brain conditions.
- Write down your questions ahead of time.
What the evaluation includes
There's no single test for dementia. Doctors put together several pieces of information.
1. Medical history and conversation
Questions about symptoms, daily functioning, mood, sleep, alcohol, past illnesses and family history. Information from someone who knows the person well is very valuable.
2. Cognitive tests
Short screening tests check memory, attention, language, and problem-solving. Common ones include the Mini-Cog, the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Exam (MMSE). They take 5 to 15 minutes. A low score doesn't diagnose dementia by itself; education, language, hearing and anxiety can affect results. Neuropsychological testing is a much more detailed assessment that can take several hours.
3. Physical and neurological exam
Checks reflexes, coordination, eye movements, speech, sensation and walking, looking for signs of stroke, Parkinson's, or other conditions.
4. Lab tests
Blood tests look for treatable causes such as vitamin B12 deficiency, thyroid problems, infections, and kidney or liver problems. See Reversible Causes of Memory Problems.
5. Brain imaging
- MRI or CT scans can show strokes, tumors, bleeding, fluid buildup (normal pressure hydrocephalus), and patterns of brain shrinkage.
- FDG-PET shows how actively brain regions use energy, which can help tell types of dementia apart.
- Amyloid PET and tau PET scans show Alzheimer's proteins in the brain.
6. Alzheimer's biomarker tests
To confirm whether Alzheimer's is the cause, doctors can measure its hallmark proteins:
- Spinal fluid (CSF) tests – a lumbar puncture measures amyloid and tau.
- Amyloid PET scan – shows amyloid plaques.
- Blood tests – In May 2025 the FDA cleared the first blood test to aid in diagnosing Alzheimer's (Fujirebio's Lumipulse plasma p-tau217/β-amyloid 1-42 ratio), for adults 55 and older with signs and symptoms of cognitive decline. Other blood tests, including ones intended for primary care, have followed. These tests are meant for people with symptoms and are interpreted together with other clinical information—not as screening tests for people without symptoms.
Biomarker confirmation is required before starting anti-amyloid drugs like Lecanemab (Leqembi) and Donanemab (Kisunla).
Getting the results
The doctor may diagnose Mild Cognitive Impairment (MCI), a type of dementia such as Alzheimer's Disease or Vascular Dementia, or another cause. Sometimes the answer is "we're not sure yet," and re-testing after 6–12 months helps. Don't hesitate to ask:
- What is causing the symptoms? How certain are you?
- What stage is it?
- What treatments are available, and what are their risks and benefits?
- Are there clinical trials we could join?
- What changes should we expect, and what should we plan for?
- Is it safe to drive, work, and manage finances?
- Where can we get support?
A second opinion is reasonable, especially for younger people or unusual symptoms.
After the diagnosis
A diagnosis can bring grief, fear—and sometimes relief at having an explanation. Take time to absorb it. Then: learn about the condition, make legal and financial plans while the person can take part, build a care team, and connect with support. See Caregiving Guide: Where to Start and Living Well with Dementia. The Alzheimer's Association Helpline (800-272-3900) and the NIA ADEAR Center (800-438-4380) can help you find next steps.
Sources
- National Institute on Aging: How Is Alzheimer's Disease Diagnosed?
- Alzheimer's Association: Medical Tests for Diagnosing Alzheimer's
- FDA: FDA Clears First Blood Test Used in Diagnosing Alzheimer's Disease (May 2025)
- Mayo Clinic: Alzheimer's disease—diagnosis
Not medical advice. This article is general information, not a diagnosis or treatment plan for any individual. Talk with a doctor about your situation.
Related articles
- 10 Early Warning Signs of Alzheimer's and Dementia
- Reversible Causes of Memory Problems
- Alzheimer's Disease
- Mild Cognitive Impairment (MCI)
Ask a question
Have a question about memory, Alzheimer's, or caregiving? Email us at:
Open in my email app · Write in Gmail (opens in a new tab)
We may answer common questions in future updates (we won't share your name). We can't give personal medical advice; for urgent help call the Alzheimer's Association Helpline at 800-272-3900.