Test : Sputum Direct Flourescent Antibody
Indications : This sputum DFA test is employed to identify the following bacteria:
• Legionella - which causes
Legionnaires’ disease
• Mycoplasma pneumonia (M. pneumonia) - which causes the less common and milder disease, “walking pneumonia”
Drink plenty of fluids the night prior to the test. Sputum sample collections is done early in the morning before eating or drinking anything. Brush teeth and rinse mouth well prior to the test. Do not use an anti-microbial mouthwash.
Breathe in deeply and cough with force to bring up sputum. Collect sputum sample up to the mark in the sterile cup. If sputum collection is difficult then it may have to be induced with the help of sterile saline or glycerin aerosol. Once sample is collected close the cup tightly, label it and send it to the laboratory.
Sputum DFA is a complex test in which specific antigens and antibodies are chemically tagged to fluorescent dye and then added to the sputum sample where they target microorganisms. The fluorescent glow in the sputum sample helps to conform the presence of pathogens in the sample.
Physiology : Sputum direct fluorescent antibody (DFA) is a test that is done to detect
pneumonia or other
lung infections. The test is also known as the direct immunofluorescence test and
Legionella DFA.
Normal Range : Negative
Interpretation : Normal
No antigen-antibody reaction is observed indicating an absence of pathogenic bacteria.
Abnormal
Fluoresce will be seen in the sputum sample indicating antigen-antibody reaction. This indicates the possibility of-
• Legionnaire's disease
• Mycoplasma pneumonia
• Chlamydia pneumonia
References :
1. http://www.nlm.nih.gov/medlineplus/ency/article/003553.htm
2. http://www.healthline.com/health/sputum-direct-fluorescent-antibody-dfa#undefined