 Sputum direct fluorescent antibody (DFA)
Definition Alternative Names 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 References DefinitionSputum direct fluorescent antibody (DFA) is a test that looks for microorganisms in lung secretions. Alternative NamesDirect immunofluorescence test; Direct fluorescent antibody - sputum How the test is performedYou 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. How to prepare for the testIf coughing does not produce sputum, a breathing treatment may be given before the test to trigger sputum production. How the test will feelThere is no discomfort. Why the test is performedYour doctor may order this test if you have signs of certain lung infections or pneumonias. Normal ValuesNormally, there is no antigen-antibody reaction. What abnormal results meanAbnormal results may be due to an infection such as Legionnaire's disease, mycoplasma pneumonia , or chlamydia pneumonia. What the risks areThere are no risks. ReferencesPhysician ReferenceCurrent Procedural Terminology (CPT)87199
Review Date: 5/23/2010
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.
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