Alzheimer’s disease (AD) cannot be diagnosed by a single test. A person showing symptoms that lead a doctor to suspect Alzheimer’s may need to undergo a series of physical, neurological, and laboratory tests to rule out other conditions and confirm a diagnosis.

During the diagnostic process, the patient may be seen by multiple specialists — such as neurologists, geriatricians, psychiatrists, and psychologists — to assess different symptoms and conduct necessary tests.

Identifying symptoms

The first step in diagnosing Alzheimer’s is recognizing that the patient is displaying common symptoms of the disease. This can include neuropsychological tests and interviews with friends and family to determine if the patient has exhibited personality, mood, and behavioral changes. The patient will be asked to complete various mental status tests to assess thinking and memory skills, and whether, based on interviews and other measures, these skills show a significant decline.

A common test used to assess changes thinking and memory abilities is the Mini Mental State Examination (MMSE).

Medical and family history

The doctor may assess the patient’s medical and family history to determine if significant risk factors exist that could lead to Alzheimer’s. Among the risk factors considered are a family history of the disease (which could point to a genetic susceptibility) or a previous medical incident (such as a traumatic head injury).

Medical history is also used to rule out other conditions that display similar symptoms, such as Parkinson’s disease or depression, or whether a person is taking a medication with side effects that mimic AD.

Brain scans

A brain scan may be recommended to assess the brain’s structure and activity, looking for signs of degeneration. Different types of brain scans are available, such as computerized tomography (CT) scan, magnetic resonance imaging (MRI) scan, and positron emission tomography (PET) scan. CT and MRI scans create detailed images of the brain, which can be used to determine whether structural changes have taken place in brain tissue. A PET scan can be useful in judging brain activity.

Results of a brain scan cannot confirm a diagnosis of AD, especially late-onset AD, as differences can be the result of normal aging. Rather, brain scans are used to rule out other potential causes — such as a stroke, tumor, hemorrhages, or trauma — and to establish a baseline to track the further changes or evidence of progression.

More precise techniques to diagnose AD are being developed and either in, or moving into, clinical trials. One such study is called IDEAS (NCT02420756), and is evaluating the use of new PET scan techniques to identify amyloid plaques, a build-up of protein fragments called beta-amyloid in the brain, which are a hallmark of AD.

Laboratory testing

A person suspected of having Alzheimer’s may also be asked to undergo additional tests, such as blood and urine tests, to further rule out a disorders that displays similar symptoms. For example, early AD symptoms like memory loss and confusion can be caused by a thyroid disorder or by vitamin B-12 deficiency.

Note: Alzheimer’s News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.