Exams and Tests

Alzheimer's disease is diagnosed after other conditions are ruled out. Your doctor will use a variety of tests to do this.

It usually is helpful to have a family member or someone in close contact with the person present at the appointment. A family member may be able to provide the best information about how a person's day-to-day functioning, memory, and personality have changed.

Initial tests

The doctor will use a medical history and physical exam to help find out if a physical problem may be causing the person's dementia symptoms. Sometimes another problem can cause the same symptoms as Alzheimer's.

The person will also have a functional status exam and a mental health assessment. During these exams, he or she will be asked to perform simple tasks.

Lab tests

Lab tests may be done to rule out other possible causes of a person's symptoms, such as levels of certain minerals or chemicals in the blood, liver disease, abnormal thyroid levels, or nutritional problems, such as folate or vitamin B12 deficiencies. Treatment for these conditions may slow or reverse mental decline.

Blood tests that may be done include:

• Complete blood count (CBC).
• Liver function tests.
• Folate (folic acid) test.
• Vitamin B12 concentration.
• Electrolyte and blood glucose levels (sodium, potassium, creatinine, glucose, calcium).
• Thyroid function tests.
• HIV test, if the person has risk factors for HIV or the medical history suggests it.

Imaging and other tests

Other tests done to rule out other causes include:

• Brain imaging tests, such as a CT head scan or an MRI of the head.
• A lumbar puncture to test for certain proteins in the spinal fluid.
• An electroencephalogram, or EEG.
• Brain imaging studies, such as positron emission tomography (PET) or single photon emission tomography (SPECT). But these tests aren't routinely done.

In some cases, examining the brain after death is done if the family wants to confirm that the person had Alzheimer's disease.