Quantitative Influenza Antibody (Nasal or Throat Swab)
Does this test have other names?
Direct immunofluorescence (DFA), indirect immunofluorescence (IFA) antibody staining.
What is this test?
This test checks for influenza antibodies in fluid from your nose or throat.
Influenza is a common illness of the respiratory system. It's often called "the flu."
It can have serious health effects. It can even cause death, especially if you have
a weakened immune system.
Influenza A is more common and can be more serious. It spreads easily through fluid
droplets in the air. It often affects many people at the same time during fall and
Healthcare providers can test for influenza in several ways. One method uses nasal
washes and throat swabs to look for influenza antigens. Results are shown quickly,
in less than 30 minutes. The test described here uses immunofluorescence. This is
a staining method to look for influenza antibodies. Results may be available in 1
to 4 hours. Results from a rapid testing method are not as accurate as a type of influenza
test called a viral culture. But a rapid test is often used as a first screening test.
A viral culture may take from 3 to10 days to show results.
Why do I need this test?
You may need this test if your healthcare provider thinks that you have the flu. Symptoms
of the flu include:
Symptoms of the flu often appear about 1 to 2 days after you are infected. The symptoms
may feel severe right away. Your body may fight off an influenza infection within
a few days. But some people develop severe pneumonia or other serious problems.
Even if you do not have signs of infection, you should be tested during flu season
or an influenza outbreak if you:
What other tests might I have along with this test?
Testing for influenza antibodies is a screening test. This means you may need additional
tests that are more accurate to confirm your diagnosis. You may have tests such as:
What do my test results mean?
Test results may vary depending on your age, gender, health history, the method used
for the test, and other things. Your test results may not mean you have a problem.
Ask your healthcare provider what your test results mean for you.
A negative result means that no influenza antibodies were found and you likely don't
have the flu.
A positive result means that you do have influenza antibodies. A positive result is
more likely to be accurate with this test if other cases of influenza have been reported
in your area. It's possible to get a false-positive result. This means that you are
not really infected with the flu. Your healthcare provider may do more tests if needed.
How is this test done?
This test is done with a sample of mucus or other fluid from your respiratory system.
Your healthcare provider will wipe a sterile swab inside your nose or throat.
Another method of doing this test is done with a nasopharyngeal aspirate (NPA). For
this, your healthcare provider will put saline solution in your nose and collect a
Does this test pose any risks?
This test does not pose any serious risks. You may feel discomfort or gag when your
throat or nasal cavity is swabbed. An NPA may also cause some discomfort.
What might affect my test results?
Other respiratory infections may cause a false-positive result. Influenza screening
tests are sometimes not accurate.
How do I get ready for this test?
You don't need to prepare for this test. Be sure your healthcare provider knows about
all medicines, herbs, vitamins, and supplements you are taking. This includes medicines
that don’t need a prescription and any illegal drugs you may use.