Diagnosing Alzheimer's Disease

According to the National Alzheimer's Association, there isn't just one test that can tell if a person has Alzheimer's disease (AD). However, new diagnostic tools make it possible for a health care provider to make a positive clinical diagnosis of AD with an accuracy of 85-90%.

The diagnostic process generally takes more than one day and will involve the primary care physician and possibly other specialty physicians, such as a psychiatrist or neurologist.

Steps to Diagnosing Alzheimer's Disease

1. Complete Medical History

This includes the patient's current mental or physical conditions, prescription medications, and family history of health problems. 

2. Mental Status Evaluation

A mental status evaluation checks how well a person knows the time and place around them, remembers things, understands questions, talks, and does basic math. The person might be asked questions like, "What year is it?" or "Who is the president?" They may also have to do simple tasks, like write a sentence or spell a word backward.

3. Physical Exam

This looks at a person's eating habits, blood pressure, and heart rate.  These tests are done to check for other possible reasons for dementia, like problems with the heart, lungs, liver, kidneys, or thyroid, as well as hardening of the arteries.

4. Neurological Exam

In a neurological exam, the provider will check the nervous system (brain and spinal cord) to see if there are any other problems, like stroke, Parkinson's disease, brain tumors, or extra fluid in the brain, that might be causing symptoms like dementia. They look at how well a person moves, how strong their muscles are, how their eyes move, how they talk, and how they use their senses. 

5. Lab Tests

The health care provider might run different tests to check for other health issues that could be causing memory problems. They do blood and urine tests to look for things like anemia, infections, diabetes, and problems with the kidneys or liver. They also check for vitamin deficiencies and thyroid hormone levels. They might also use scans like CT or MRI to see if there are tumors, strokes, or blood clots that could be affecting memory and thinking.

6. Psychiatric, psychological, and other evaluations

These tests help check for other illnesses, like depression, that might cause similar symptoms to Alzheimer's disease. They look at things like memory, thinking skills, writing, vision and movement skills, and how well a person can share their ideas. This gives more detailed information than just a basic mental check.

There is no single test that can confirm someone has Alzheimer's disease (AD). However, various tests can help health care providers rule out other causes of symptoms that look like dementia. After all the tests are done, the provider will look at the results to give a diagnosis. If the results suggest Alzheimer's, they usually call it "probable Alzheimer's disease" or "dementia of the Alzheimer type." If the symptoms don’t match typical Alzheimer's but no other cause is found, it might be labeled as "possible Alzheimer's disease." The only way to know for sure if someone had Alzheimer's is to examine their brain after they pass away.

For information on diagnosing Alzheimer’s disease, visit the Alzheimer’s Association: Diagnosis Information | en español: Diagnostico

*Dementias are a variety of syndromes involving loss of cognitive or intellectual functioning such as thinking, remembering and reasoning, so severe that it interferes with an individual's daily functioning. Changes in personality and behavior, and motor impairment are also associated with various dementias.