Serology for tularemia

Definition

This blood test looks for antibodies against Francisella tularensis, the bacteria that causes the disease tularemia.

How the test is performed

An antibody defends the body against bacteria, viruses, fungus, or other foreign body (antigen). Certain cells tell the body to produce antibodies during an active infection.

In the initial stage of an illness, few antibodies may be detected. Antibody production increases during the course of an infection. For this reason, such tests are often repeated several weeks after the first test is done.

This test specifically looks for the antibodies in the clear liquid portion of the blood, which is called the serum. (This technique is called serology.)

How to prepare for the test

There is no special preparation.

How the test will feel

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

This blood test may be performed when tularemia is suspected.

Normal Values

No antibodies are detected. However, during the first few days to weeks of exposure to an antigen, there may be slight antibody production. As the disease progresses, more antibodies will be present. If a disease is suspected, the test may need to be repeated several weeks after the first test.

What abnormal results mean

If antibodies are detected, there has been exposure to Franciscella tularensis (possible tularemia).

What the risks are

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins

Special considerations

A serology test can determine if a patient has ever been exposed to a particular antigen, but this does not necessarily indicate a current infection. Increasing antibody levels are more likely to indicate a current infection.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Illustrations

Blood test

Page Content:

Tularemia test; Serology for Francisella tularensis