Health Encyclopedia

Coccidioidin skin test

Definition

The coccidiodin skin test checks to see if you are infected with the fungus that causes coccidioidomycosis.

The spherulin test also looks for this fungus, but it may be a more sensitive test. That means it may pick up signs of the infection earlier or more accurately.

Alternative Names

Spherulin skin test

How the test is performed

Coccidiodin and spherulin are substances called antigens that are specifically associated with the fungus that causes coccidioidomycosis.

One of these substances is injected just below the skin's surface, usually in the forearm. Your health care provider will look at your arm 24 hours and 48 hours after the test. If your body has antibodies to the coccidiomycosis fungus, your body will react to the antigen. The area of the shot will become red.

How to prepare for the test

No special preparation is necessary.

How the test will feel

There will be a brief sting as a needle is inserted just below the skin's surface.

Why the test is performed

Doctors once ordered this test if a patient had signs or symptoms of coccidioidomycosis, or had been exposed to the fungus that causes the disease.

However, this skin test is no longer used to diagnosis patients. It is not specific and is mostly used in research to better understand the causes, spread, and control of the disease among a specific group of people.

Normal Values

A normal result means you had no reaction (inflammation) to the antigen contained in the shot.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

An abnormal result (positive result) means you have been exposed to the fungus that causes the disease. However, the exposure may have been in the distant past and may not reflect a current infection. Many people who live in areas where this infection is common may have a positive result but not an active infection.

The test can be positive 2 to 21 days after you develop symptoms. However, many patients do not have a positive reaction even when they have the disease.

False-positives are possible. You may have a positive reaction when you have been exposed to a fungus other than the one that causes coccidiomycosis.

What the risks are

There is a slight risk of anaphylactic shock (a severe reaction) associated with this skin test.

References

Chiller TM. Coccidioidomycosis. Infect Dis Clin North Am. 2003;17(1):41-57.

Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 5th ed. London, UK: Churchill Livingstone; 2000:2746-2755.

Galgiani JN, Ampel N, Blair JE, et al. Coccidioidomycosis. Clin Infect Dis. 2005;41:1217-1223.

Review Date:12/3/2007
Reviewed By:D. Scott Smith, M.D., MSc, DTM&H, Chief of Infectious Disease & Geographic Medicine, Kaiser Redwood City, CA & Adjunct Assistant Professor, Stanford University. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.