| Subject | Contents |
| Definition | This is a laboratory technique (immunologic testing) to detect antibodies in the blood resulting from exposure to the fungus Apergillus . |
| Alternative Names | Aspergillus immunodiffusion test; Test for precipitating antibodies |
| How the test is performed | Adult or child: Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (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 tourniquet 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 . 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 | Adults: There is no special preparation. Infants and children: The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age: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 | 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 | The test is performed when a fungal infection is suspected. |
| Normal Values | The normal test result is negative for aspergillus antibodies . |
| What abnormal results mean | Precipitin are found in 95% of cases involving a fungus ball. Hypersensitivity pneumonitis (allergic bronchopulmonary Aspergillosis, also called ABPA) has precipitins in about half the cases. Invasive aspergillosis often has a falsely negative precipitin test (Aspergillus is present, but the test is negative.) |
| What the risks are | The risks are associated with a venipuncture : Excessive bleedingFainting 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 | 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. |
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