Coccidioidomycosis antibody test
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.
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 It has mostly been replaced by immunodiffusion tests.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)
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.
Galgiani JN. Coccidioidomycosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 354.
Galgiani JN. Coccidioides species. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 266.
Last reviewed 6/9/2011 by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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