Coccidioides precipitin test

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Coccidioides precipitin is a blood test that looks for infections due to a fungus called Coccidioides, which causes the disease coccidioidomycosis.

Alternative Names

Coccidioidomycosis antibody test

How the Test is Performed

A blood sample is needed.

The sample is sent to a laboratory. There, it is examined for bands called precipitin that form when antibodies are present.

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 or bruising. This soon goes away.

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, which causes the disease coccidioidomycosis.

Antibodies defend the body against bacteria, viruses, and fungi. These and other foreign substances are called antigens. When you are exposed to antigens, your body produces antibodies.

The precipitin test helps check if the body has produced antibodies to a specific antigen, in this case, the Coccidioides fungus. 

Normal Results

A normal result is when no precipitins are formed. This means the blood test did not detect the antibody to Coccidioides.

What Abnormal Results Mean

An abnormal (positive) result means the antibody to Coccidioideshas been detected.

In this case, another test is done to confirm that you have an infection. Your doctor can tell you more.

During the early stage of an illness, few antibodies may be detected. Antibody production increases during the course of an infection. For this reason, this test may be repeated several weeks after the first test. 


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 lightheaded
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)



Galgiani JN. Coccidioidomycosis (Coccidioides species). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 267.

Iwen PC. Mycotic diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 61.

Version Info

  • Last reviewed on 5/1/2015
  • 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, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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