Sputum DFA (direct fluorescent antibody)Definition: Sputum DFA is a test performed to detect the presence of microorganisms in sputum (lung secretions) by using antibodies tagged with a fluorescent dye.
Alternative Names: Direct immunofluorescence test
How the test is performed: A sputum sample is obtained by coughing into a specimen container. In the laboratory, antibodies that have been chemically linked to a fluorescent dye are added to the sample. The flagged antibodies will attach themselves to the specific antigens (in this case, the microorganism against which they were formed). The specific microorganism (antigen) is indirectly identified by the presence of fluorescence when examined under a special microscope.
How to prepare for the test: Obtain a coughed sputum specimen. If there is not a productive cough, a respiratory treatment may produce a sample.
How the test will feel: There is no discomfort.
Why the test is performed: This test may be performed when certain types of pulmonary infections or pneumonias are suspected.
Normal Values: Normally, there is no antigen-antibody reaction. A reaction indicates infection.
What abnormal results mean: Abnormal results may indicate a specific infection depending on the antigens tested. Legionnaire's disease�or mycoplasmal pneumonia are 2 infections that can be determined by this test.
What the risks are: There are no risks.
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