Definition of Histoplasma complement fixation:

Histoplasma complement fixation is a blood test that checks for signs of infection due to a fungus called Histoplasma capsulatum (H. capsulatum). Some people who breathe in particles of this fungus may get an infection called histoplasmosis.

See also:

• Histoplasmosis - chronic pulmonary
• Histoplasmosis - disseminated
• Histoplasmosis - acute (primary) pulmonary
• Histoplasmosis - skin lesion

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture

The complement fixation test looks to see if the body has produced antibodies to a certain antigen (a substance that triggers an immune response) -- in this case, the Histoplasma capsulatum fungus. If antibodies are present, they attach to the antigen. This combination activates, or "fixes" complement, and this activation can be measured. That is why the test is called "complement fixation."

The test looks for antibodies in the clear liquid part of the blood (serum). The general term for this method is called serology.

How to prepare for the test:

There is no special preparation for the test.

How the test will feel:

You may feel a prick or stinging sensation when the needle is inserted to draw your blood. Some people may have moderate pain. Afterward, there may be some throbbing.

Why the test is performed:

Histoplasma complement fixation is one of the most commonly used methods to test for a fungal infection caused by H. capsulatum.