Sputum direct fluorescent antibody (DFA)
Toggle: English / Spanish
Sputum direct fluorescent antibody (DFA) is a test that looks for microorganisms in lung secretions.
Direct immunofluorescence test; Direct fluorescent antibody - sputum
How the test is performed
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,
that have been chemically linked to a fluorescent dye are added to the sample. These antibodies are considered "tagged." They will attach to specific -- 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 test
If coughing does not produce sputum, a breathing treatment may be given before the test to trigger sputum production.
How the test will feel
There is no discomfort.
Why the test is performed
Your doctor may order this test if you have signs of certain lung infections or pneumonias.
Normally, there is no antigen-antibody reaction.
What abnormal results mean
Abnormal results may be due to an infection such as
, , or chlamydia pneumonia.
What the risks are
There are no risks.
Limper AH. Overview of pneumonia. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 97.
- Last reviewed on 5/28/2012
- 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. Health Solutions, Ebix, Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.