Definition of Complement fixation test to C. burnetii:

The complement fixation test to C. burnetii is used to detect the presence of antibodies to Coxiella burnetii (C. burnetii) bacteria in the blood. These highly infectious bacteria cause Q fever.

How the test is performed:

Antibodies defend the body against some bacteria, viruses, fungi, and other foreign substances, called antigens. Certain cells cause the body to produce antibodies during an active infection.

When you first become sick, few antibodies may be detected. Antibody production increases during the course of an infection. Antibody tests are often repeated several weeks after the first test is done, so that a comparison can be made to the first test. A rising level of antibody to a specific bacteria or virus tells the health care provider that you had an active infection.

The complement fixation test looks to see if the body has produced antibodies to a specific antigen -- in this case, the C.burnetii bacteria. If the antibodies are present, they attach to the antigen. This combination activates or "fixes" complement.

The test specifically looks for the antibodies to C. burnetii in the clear liquid portion of the blood called the serum. (The term for this technique is serology.) If you have persistently high levels of antibodies to C. Burnetii, you could have chronic Q fever.

How to prepare for the test:

No special preparation is necessary for this test.

How the test will feel:

You may feel moderate pain when the needle is inserted, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

The test is performed to detect Q fever.