Sputum direct fluorescent antibody (DFA) is a lab test that looks for micro-organisms 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. (Mucus is not the same as saliva or spit from the mouth.)
The sample is sent to a lab. There, a fluorescent dye is added to the sample. If micro-organisms are 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 with this test.
Why the Test is Performed
Your doctor may order this test if you have signs of certain lung infections.
Normally, there is no antigen-antibody reaction.
What Abnormal Results Mean
Abnormal results may be due to an infection such as:
Legionnaire disease Pneumoniadue to certain bacteria, viruses, fungi, or other micro-organisms
There are no risks with this test.
Banaei N, Deresinski SC, Pinsky BA. Microbiologic diagnosis of lung infection. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 19.
Patel R. The clinician and the microbiology laboratory: test ordering, specimen collection, and result interpretation. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 16.
Review Date: 29/04/2022
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician 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. Copyright ©2019 A.D.A.M., Inc., as modified by University of California San Francisco. Any duplication or distribution of the information contained herein is strictly prohibited.
Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Health. Please discuss with your doctor any questions or concerns you may have.