Coccidioides complement fixation
Coccidioides antibody test; Coccidioidomycosis blood testCoccidioides complement fixation is a blood test that looks for substances (proteins) called antibodies, which are produced by the body in reaction to the fungus Coccidioides immitis. This fungus causes the disease coccidioidomycosis.
Antibodies
An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples of antigens include micr...
Coccidioidomycosis
Valley fever is an infection that occurs when the spores of the fungus Coccidioides immitis enter your body through the lungs.
How the Test is Performed
Blood sample is needed
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
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, some people feel moderate pain, while others feel only a prick or stinging. Afterward, there may be some throbbing.
Why the Test is Performed
This test is used to detect infection with the fungus that causes coccidioidomycosis, or Valley fever. This condition can cause lung (localized) or widespread (disseminated) infection.
Normal Results
A normal result means no Coccidioides immitis antibodies are detected in the blood sample.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
Abnormal results mean that Coccidioides immitis antibodies are present. This can mean that you have a current or past infection.
The test may be repeated after several weeks to detect a rise in titer (antibody concentration), which confirms an active infection.
Titer
A titer is a measurement of the amount or concentration of a substance in a solution. It usually refers to the amount of antibodies found in a perso...
In general, the worse the infection, the higher is the titer, except in people with a weakened immune system.
There can be false positive tests in people with other fungal diseases such as histoplasmosis and blastomycosis, and false negative tests in people with single lung masses from coccidioidomycosis.
Histoplasmosis
Histoplasmosis is an infection that occurs from breathing in the spores of the fungus Histoplasma capsulatum.
Blastomycosis
Blastomycosis is an infection caused by breathing in the Blastomyces dermatitidis fungus. The fungus is found in decaying wood and soil.
Risks
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood 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 lightheaded
- Multiple punctures to locate veins
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Galgiani JN. Coccidioidomycosis (Coccidioides species). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 265.
Iwen PC, Thompson GR, Wiederhold NP. Mycotic diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 60.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 8/26/2023
Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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