Laboratory tests are the most certain sources of finding out if you suffer of a grave disease with symptoms which can affect more than you thought your life. Of course, blood tests are the most frequently done laboratory analysis in order to find out if a person suffers or not of a grave disease with symptoms which rarely can be treated, or worst, if these symptoms will allow to live just eight or ten years more.

Blood tests useful to diagnose the Alzheimer's disease, but also other disease are:
- Blood count, which highlights the number and type of blood cells and helps in the diagnosis
- Liver function tests (ALT, AST, alkaline phosphatase) to diagnose liver disease
- Determination of folic acid. Folic acid is needed to produce both red cells and white blood cells
- Vitamin B12 concentrations in blood. Vitamin B12 is useful in producing red blood cells in maintaining nervous system health
- Determination of electrolytes and glucose levels (sodium, potassium, glucose, calcium). Electrolytes are useful in maintaining fluid balance in the body at an optimum level and maintain normal functions (ex heart rate, muscle contraction and function of neurons)



- Thyroid function tests. Abnormal thyroid hormone levels are a common cause of symptoms like memory loss, confusion, lethargy and other symptoms of dementia in older people. Drug therapy improves symptoms in people with thyroid function disorders

- Screening for syphilis. Dementia occurs in the last stage of syphilis (tertiary syphilis). If the person had syphilis long ago and it was not properly treated, the disease may progress to affect behavior and intelligence impairment can occur. Although syphilis is a disease becoming more rare, are tests to determine it, because it is a curable disease

- Test for detection of human immunodeficiency virus (HIV). AIDS untreated can cause symptoms as personality disorders or concentration problems  Imaging like CT scan or MRI are performed to rule out other causes when the diagnosis is uncertain. May be an electroencephalogram (EEG) to monitor brain electrical activity in case the patient has a history of seizure phenomena.  In some cases examining brain autopsy is performed to highlight at this level of changes that may indicate Alzheimer's disease.



Although an autopsy is the only way to make with certainty the diagnosis of Alzheimer's disease, changes in the initial stages of the disease may not be very clear to make the diagnosis. An autopsy is rarely necessary but can be made when the family wants to know with certainty whether or not Alzheimer's.

-Early detection: At this time there is no screening for Alzheimer's. It is difficult to diagnose this disease in its early stages. However the symptoms of mental decline should not be ignored and attributed to aging. Genetic tests for detecting gene for protein E-4 may become useful as they will know more about genetic causes of disease. These tests are not widely used at this time.