Sputum direct fluorescent antibody (DFA) is a test that looks for microorganisms in lung secretions.

Direct immunofluorescence test; Direct fluorescent antibody - sputum

You will produce a sputum sample from your lungs by coughing up mucus from deep inside your lungs. (The mucus is not the same as saliva or spit from the mouth.)

In the laboratory, antibodies that have been chemically linked to a fluorescent dye are added to the sample. These antibodies are considered "tagged." They will attach to specific antigens -- in this case, the microorganism against which they were formed. If the specific microorganism is present, a bright glow (fluorescence) can be seen in the sputum sample using a special microscope.

If coughing does not produce sputum, a breathing treatment may be given before the test to trigger sputum production.

There is no discomfort.

Your doctor may order this test if you have signs of certain lung infections or pneumonias.

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Sputum direct fluorescent antibody (DFA) Results

Review Date: 05/23/2010
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)