Sputum direct fluorescent antibody (DFA) test
Sputum Direct Fluorescent Antibody (DFA) Test
A sputum direct fluorescent antibody (DFA) test is used to diagnose infections caused by certain types of bacteria. It uses a combination of fluorescent antibodies and a microscope to check for the presence of certain bacteria in a sample of sputum. The test is also known as a fluorescent antibody (FA) test.
The DFA test is used primarily to detect the presence of Streptococcus pneumoniae or Haemophilus influenzae in the lungs. It is also used to identify other types of bacteria, including some respiratory pathogens, such as Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila.
Preparation for a Sputum Direct Fluorescent Antibody (DFA) Test
Before performing the test, a health care provider may order other tests to confirm or rule out the presence of an infection. Such tests may include a chest X-ray, a throat swab, a urine culture, or a blood culture. The collected samples will be sent to the lab for analysis.
In preparation for the DFA test, the patient will need to provide a sample of sputum. That means the patient must be able to cough up some mucus from the lungs. If the patient is unable to do it, the health care provider may give the patient medication or warm liquids to loosen the sputum. The sputum sample will then be taken to the lab to be analyzed.
Procedure for a Sputum Direct Fluorescent Antibody (DFA) Test
The sample will be placed on a slide and examined under a microscope. Any bacteria that are present in the sample will be stained using a special antibody that fluoresces under ultraviolet light. The fluorescence will indicate the presence of the bacteria, allowing the technician to identify which bacteria are present in the sputum sample.
Once the bacteria have been identified, the lab technician will record the results and the sample will be sent to a hospital or health care provider for further analysis. If the results are positive, the health care provider will proceed with the appropriate treatment for the infection.
Types of Bacteria Detected by a Sputum Direct Fluorescent Antibody (DFA) Test
The DFA test is used to detect the following types of bacteria:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- Legionella pneumophila
Risks of a Sputum Direct Fluorescent Antibody (DFA) Test
The DFA test is a relatively safe and noninvasive procedure. There is a minimal risk of infection from a DFA test, as all samples are collected under tightly controlled conditions. Additionally, the test does not require any radiation.
Why is a Sputum Direct Fluorescent Antibody (DFA) Test Done?
A sputum DFA test is done to diagnose an infection that is caused by certain types of bacteria. It is particularly useful for diagnosing respiratory infections, which can be difficult to identify with other tests. Since the test is quick and accurate, it is often used in situations where a diagnosis is needed quickly.
When is the Sputum Direct Fluorescent Antibody (DFA) Test Used?
The DFA test is used when infections caused by certain types of bacteria are suspected. It is also used to differentiate between types of bacteria that may be present in the sputum, as the fluorescent antibody will only bind to specific types of bacteria. The DFA test may also be used to confirm a diagnosis that was made using other methods, such as a throat swab or blood test.