Histoplasma skin test

Definition

Histoplasma skin test is a method to check if you have been exposed to a fungus called Histoplasma capsulatum. The fungus causes an infection called histoplasmosis.

How the test is performed

The health care provider will clean an area with hair, usually the forearm. An allergen is injected just below the cleaned skin surface. 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.

How to prepare for the test

No special preparation is necessary for this test.

How the test will feel

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

Why the test is performed

This test is used to determine if a person has been exposed to the fungus that causes histoplasmosis.

Normal Values

No reaction (inflammation) at the site of the test is normal. Of note, the skin test can sometimes make histoplasmosis antibody tests turn positive.

What abnormal results mean

A reaction means the person has been exposed to the histoplasmosis fungus.

What the risks are

There is a slight risk of anaphylactic shock (a severe reaction).

Special considerations

This test is rarely used today. It has been replaced by a variety of blood tests.