The histoplasma skin test is used to check if you have been exposed to a fungus called Histoplasma capsulatum. The fungus causes an infection called histoplasmosis.
The health care provider cleans an area of your skin, usually the forearm. An allergen is injected just below the cleaned skin surface. An allergen is a substance that causes an allergic reaction. The injection site is checked at 24 hours and at 48 hours for signs of a reaction. Occasionally, the reaction may not appear until the fourth day.
No special preparation is necessary for this test.
You may feel a brief sting as the needle is inserted just below the skin.
This test is used to determine if you have been exposed to the fungus that causes histoplasmosis.
No reaction (inflammation) at the site of the test is normal. The skin test can rarely make histoplasmosis antibody tests turn positive.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
A reaction means you have been exposed to Histoplasma capsulatum. It does not always mean you have an active infection.
There is a slight risk of anaphylactic shock (a severe reaction).
This test is rarely used today. It has been replaced by a variety of blood and urine tests.
Reviewed By: 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, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.