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Coccidioides complement fixation

Coccidioides 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.

How the Test is Performed

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 or widespread (disseminated) infection.

Normal 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.


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.




  • Excessive bleeding
  • Fainting or feeling lightheaded
  • Multiple punctures to locate veins
  • Hematoma (blood accumulating under the skin)

Alternative Names

Coccidioides antibody test; Coccidioidomycosis blood test 





Review Date 8/25/2019
