Getting a proper diagnosis

A diagnosis of Alzheimer’s should come at the end of a process, not at the start. Some memory problems come from things that can be treated. Even when Alzheimer’s is present, fixing one of these can make a real difference to how your mother gets through the day.

Rule out the look-alikes first

The Alzheimer’s Association and the CDC both say some memory problems come from treatable conditions. Dementia that goes away completely once treated is uncommon. Finding a treatable problem that is making things worse is common, and treating it can help even when Alzheimer’s is also there.

Medicines

This is the most common fixable contributor. The American Geriatrics Society’s Beers Criteria (updated May 2023) list drugs that can cause confusion, memory problems or delirium in older adults. They include:

• Benzodiazepines such as lorazepam, alprazolam and diazepam, and “Z-drug” sleeping pills.
• Strongly anticholinergic drugs such as diphenhydramine (Benadryl and many “PM” sleep aids), some bladder drugs such as oxybutynin, and older antidepressants such as amitriptyline.
• Certain muscle relaxers and antipsychotics.

Ask for a “brown bag” review: put every pill, supplement and over-the-counter product in a bag and take it to the doctor or pharmacist. Ask, “Is anything here anticholinergic or sedating?”

Harmful3/5Funder not confirmed

Long-term use of strong anticholinergic drugs and dementia

Gray SL et al., JAMA Internal Medicine 2015;175(3):401–407 Read the study

Design

Prospective cohort (observational)

People

3,434 adults aged 65+ without dementia at the start

Length

7.3 years on average

Result People with the highest long-term use (more than 3 years’ worth of daily doses) had a 54% higher risk of dementia (hazard ratio 1.54). The more they took, the higher the risk. The drugs were older antidepressants, older antihistamines such as diphenhydramine, and bladder drugs. This shows a link, not proof that the drugs cause dementia, and it does not show whether stopping them lowers the risk.

Who paid: Not yet confirmed.

Conflicts: Not reported

Vitamin B12 deficiency

Low B12 is common in older adults. A stomach condition called atrophic gastritis affects about 8–9% of people 65 and over (roughly 1 in 12), and the diabetes drug metformin and acid-reducing drugs called PPIs (such as omeprazole) lower absorption. Low B12 can cause numbness, tingling and thinking problems. It should be treated early to avoid lasting damage. Ask for: a blood B12 level, plus methylmalonic acid if B12 is borderline. B12 supplements do not improve memory in people who are not low. See nutrition and deficiencies.

Underactive thyroid

The Alzheimer’s Association and CDC name thyroid problems as a treatable cause of memory problems. Ask for: a TSH blood test.

Normal-pressure hydrocephalus (NPH)

This is a build-up of fluid in the brain. The classic signs are a shuffling walk where the feet seem stuck to the floor, needing to pee urgently or leaking, and slowed thinking. The walking problem usually comes first. Cleveland Clinic reports that a surgical drain (shunt) improves walking in about 85% and thinking in about 80% of people treated early. Ask for: an MRI, then a “tap test”, where some spinal fluid is removed to see whether walking improves.

Depression

Depression is on the standard checklist of things to rule out. It is also on the Lancet list of dementia risk factors. Ask for: a depression screen, such as the PHQ-9 or the Geriatric Depression Scale.

Infection and sudden confusion

A urine test is on the Alzheimer’s Association’s list of standard tests, because infections such as a urinary tract infection can cause confusion. Alzheimer’s usually gets worse slowly. A sudden change over hours or days is different, and needs a call to the doctor the same day. Ask for: a urine test, blood count, metabolic panel and oxygen level.

Sleep apnea

Sleep apnea is named as a condition to rule out. Ask for: a sleep study if she snores loudly, stops breathing in her sleep or is very sleepy in the day.

Alcohol

Heavy drinking can cause memory loss. Give the doctor an honest picture. Doctors often check thiamine (vitamin B1) in heavy drinkers, because severe lack of it damages memory; we have not yet confirmed the details from a primary source.

Hearing and vision

Poor hearing can make a person seem confused and cuts them off from conversation. Hearing loss and untreated vision loss are both on the Lancet list of risk factors. Ask for: a hearing test and an eye exam. The main hearing-aid trial is covered on lowering your risk.

• ACHIEVE: hearing aids and thinkingLin FR et al., The Lancet 2023 · 977 older adults with hearing loss · 3 years

  Promising4/5Public / nonprofit

Stroke, bleeding and tumors

A brain scan looks for strokes, tumors, bleeding and NPH. If she has had a fall, tell the doctor, even a minor one.

What tests to ask for

A reasonable minimum, based on the Alzheimer’s Association list of medical tests:

1. A complete medication review, including over-the-counter drugs and supplements.
2. Blood tests: complete blood count, metabolic panel (kidney, liver, sodium, calcium, glucose), TSH and B12, plus a urine test.
3. A depression screen, and hearing and vision checks.
4. Questions about snoring, sleep and alcohol.
5. A brain MRI or CT scan.
6. A formal thinking test, repeated over time.

If your mother has Medicare, ask for a cognitive assessment and care plan visit (billing code 99483). It is a visit of about an hour with her and a family member. It covers a thinking exam, how she manages daily tasks, staging, a review of risky medicines, home and driving safety, and a written care plan. It can be done in the office, at home or by video. More on this is on the first 30 days page.

Screening tests in the office

• Mini-Cog: remembering three words plus drawing a clock. Short enough for a normal primary-care visit.
• Longer paper tests such as the MoCA and the MMSE.
• Others: SLUMS, the AD8 (a questionnaire filled in by a family member), the Functional Activities Questionnaire, and computer-based tests.

Screening tests do not diagnose. A poor score means a full evaluation is needed.

Brain scans

• MRI or CT rules out stroke, tumor, bleeding and NPH, and shows patterns of shrinkage.
• Amyloid PET scan shows plaques directly. In October 2023 Medicare dropped its national limit of one scan per lifetime, and local Medicare contractors now decide coverage (we have seen the decision’s title and news reports, not the full text). Without coverage, a scan costs about $3,000–6,000.
• Tau PET scan shows where tangles are. It is used mostly in research.

Biomarker tests

A biomarker test looks for the biology of Alzheimer’s, amyloid and tau, rather than only the symptoms.

• Spinal fluid test. A lumbar puncture (spinal tap) measures amyloid and tau. It is accurate, but it is a needle in the lower back.
• Amyloid PET, above.
• Blood tests, below. These are new, and they are changing fast.

The new blood tests

As of September 2026 the FDA has cleared four blood tests to help diagnose Alzheimer’s. All four are for people who already have symptoms. None is approved for screening healthy people. Each result has to be read alongside a full medical evaluation. No single test diagnoses Alzheimer’s.

Accuracy figures come from the FDA and the makers; we have not found independent figures yet. For Lumipulse, “positives correct” means the person also had amyloid on a PET scan or spinal fluid test, and under 20% of people got an “indeterminate” result. Elecsys pTau217 is the first single-marker test cleared to both rule Alzheimer’s in and rule it out, and it reports positive, intermediate or negative.

What the experts recommend. The Alzheimer’s Association’s July 2025 guideline for specialists says a blood test that catches at least 90% of true cases and correctly clears at least 75% of people without the disease can be used as a first check. A positive result then needs confirming with a PET scan or spinal fluid test. Only a test that reaches 90% on both measures can replace PET or spinal fluid. Many commercial tests do not meet these bars.

Cost and coverage are unsettled. The FDA-cleared tests have no public list price. Lab tests sold straight to consumers, which are not FDA-cleared, cost roughly $277–$626 at Labcorp, $300–$486 at Lucent and from $399 at Quest, according to Being Patient. One source puts out-of-pocket costs at about $500–1,000. Reports disagree about whether Medicare pays for these tests for people with symptoms, and we could not confirm a national Medicare policy. Ask the doctor and the lab about cost before the blood draw.

The 2024 argument over what counts as Alzheimer’s

Two expert groups now disagree about what the word “Alzheimer’s” should mean.

• The Alzheimer’s Association workgroup (Jack and colleagues, June 2024) defines Alzheimer’s by biology. An abnormal core biomarker (amyloid PET, or a blood or spinal-fluid p-tau217 or amyloid test) is enough to say someone has Alzheimer’s disease, even with no symptoms. It adds staging based on tau. It still says clinical biomarker testing is meant for people with symptoms, not for people whose thinking is normal.
• The International Working Group (Dubois and colleagues, JAMA Neurology, November 2024) disagrees. It says people with normal thinking and positive biomarkers should be called “at risk”, not “having Alzheimer’s”. It warns about false positives and turning healthy people into “patients in waiting”.

For families, the practical point is simple. A positive amyloid test in someone without symptoms is not a dementia diagnosis. If a relative without symptoms is thinking of ordering a direct-to-consumer test, talk it through with a doctor first.

Questions to ask the doctor

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Once you have a diagnosis, the first 30 days page walks through the legal, money and safety steps. For treatments, see medicines and clinical trials.

Words used on this page

Anticholinergic

A drug that blocks acetylcholine, a chemical messenger the brain uses for memory. Many allergy, sleep, bladder and older antidepressant drugs do this.

Biomarker

Something that can be measured in the body, such as a protein in blood or spinal fluid, that shows a disease process is present.