MedlinePlus Medical Encyclopedia: Aspergillosis precipitin

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Aspergillosis precipitin

Contents of this page:
Illustrations Alternative names Definition How the test is performed How to prepare for the test How the test will feel	Why the test is performed Normal Values What abnormal results mean What the risks are Special considerations

Illustrations

Blood test

Alternative names Return to top

Aspergillus immunodiffusion test; Test for precipitating antibodies

Definition Return to top

This is a laboratory test to detect antibodies in the blood resulting from exposure to the fungus Aspergillus.

How the test is performed Return to top

Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

Using immunologic testing techniques, the blood sample is examined for precipitin bands that form when aspergillus antibodies are present.

How to prepare for the test Return to top

There is no special preparation.

For infants and children:
The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following topics:

Infant test or procedure preparation (birth to 1 year)
Toddler test or procedure preparation (1 to 3 years)
Preschooler test or procedure preparation (3 to 6 years)
Schoolage test or procedure preparation (6 to 12 years)
Adolescent test or procedure preparation (12 to 18 years)

How the test will feel Return to top

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed Return to top

The test is performed when a fungal infection is suspected.

Normal Values Return to top

The normal test result is negative for aspergillus antibodies.

What abnormal results mean Return to top

Precipitins are found in 95% of cases involving a fungus ball. About half of hypersensitivity pneumonitis (allergic bronchopulmonary Aspergillosis, also called ABPA) cases have precipitins. Invasive aspergillosis often gives a false-negative precipitin test (Aspergillus is present, but the test is negative.)

What the risks are Return to top

The risks are associated with having blood drawn:

Excessive bleeding
Fainting or feeling light-headed
Hematoma (blood accumulating under the skin)
Infection (a slight risk anytime the skin is broken)
Multiple punctures to locate veins

Special considerations Return to top

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.

Update Date: 1/19/2004

Updated by: Daniel Levy, M.D., Ph.D., Infectious Diseases, Greater Baltimore Medical Center, Baltimore, MD. Review provided by VeriMed Healthcare Network.

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