Definition of Coccidioides precipitin:

Coccidioides precipitin is a blood test that looks for antibodies to the fungus Coccidioides immitis, which causes the disease coccidioidomycosis.

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture.

This test looks for the antibodies in the clear liquid portion of the blood, which is called the serum. An antibody defends the body against some bacteria, viruses, fungus, or other foreign substance. Certain cells tell the body to produce antibodies during an active infection.

How to prepare for the test:

There is no special preparation for the test.

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:

The precipitin test is one of several tests that can be done to determine if you are infected with the fungus Coccidioides immitis, which causes the disease coccidioidomycosis.

Normal Values:

No precipitins is normal. This means the blood test did not detect the antibody to Coccidioidies immitis.

What abnormal results mean:

An abnormal (positive) result means the antibody to Coccidioides immitis has been detected.

In this case, another test is done to confirm that you have an infection. See: CSF coccidioides complement fixation. This test is rarely done. It has mostly been replaced by immunodiffusion tests.

What the risks are:

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.

Other risks associated with having blood drawn are slight but may include:

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

Special considerations:

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.