Sputum direct fluorescent antibody (DFA) test: MedlinePlus Medical Encyclopedia

P Sputum direct fluorescent antibody (DFA) is a lab test that looks for micro-organisms in lung secretions.

T How the Test is Performed
P 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.)
P The sample is sent to a lab. There, a fluorescent dye is added to the sample. If the micro-organism is present, a bright glow (fluorescence) can be seen in the sputum sample using a special microscope.

T How to Prepare for the Test
P If coughing does not produce sputum, a breathing treatment may be given before the test to trigger sputum production.

T How the Test will Feel
P There is no discomfort with this test.

T Why the Test is Performed
P Your doctor may order this test if you have signs of certain lung infections.

T Normal Results
P Normally, there is no antigen-antibody reaction.

T What Abnormal Results Mean
P Abnormal results may be due to an infection such as:
- Legionnaire disease
- Pneumonia due to certain bacteria

T Risks
P There are no risks with this test.

T Alternative Names
P Direct immunofluorescence test; Direct fluorescent antibody - sputum

T References
P Banaei N, Deresinski SC, Pinsky BA. Microbiologic diagnosis of lung infection. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 17.
P Murray PR. The clinician and the microbiology laboratory. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 16.

T Review Date 5/20/2016
P Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

