Diagnosing and Testing for Swine Flu
Most people wondering if they have the H1N1 swine flu will be diagnosed by their doctor, based on symptoms rather than a lab test. There are a few reasons testing is not routinely completed:
- The Centers for Disease Control (CDC) is no longer tracking each case of swine flu.
- Doctors are familiar with symptoms of the flu and are able to make a diagnosis without a test.
- Treatment is the same whether you have the flu or have a viral respiratory infection.
Although the majority of people will not receive testing for swine flu, there are certain groups that should be tested: if you are at high risk for developing complications from the flu, if you have a compromised immune system or if you are in the hospital.
Rapid Flu Test
Rapid flu tests can be taken in a doctor's office or urgent care clinic and do not need to be sent to a laboratory for results. Results are normally available anywhere from about 10 minutes to about 30 minutes.
Testing is performed with a nasal swab and mucus is taken from either the back of the nose or the back of the throat. A nasal wash can also be used. This is when a small amount of fluid is squirted into the nose and then suctioned back out.
There are several different rapid flu tests available. They test for influenza type A and type B, but do not specifically test for H1N1 swine flu. Accuracy is also a concern with this type of test. Rapid flu tests are up to 70 percent accurate. A positive result normally indicates that the person has influenza, however, a negative result does not completely rule out an influenza diagnosis. Some research has shown these types of tests are more accurate in children than in adults.
H1N1 Specific Testing
There are currently two different tests to determine whether someone has contracted H1N1 swine flu.
Viral culture - Viral cultures can provide specific information on influenza characteristics, are very accurate and are an important source of information for public agencies. This type of testing, however, takes too long to receive results to help with deciding on treatment.
Real-time Reverse Transriptase Polymerase Chain Reaction - This type of test is specialized and can determine whether H1N1 swine flu is present. This test also takes several days to receive results.
The CDC is recommending specific testing for H1N1 swine flu only for those patients who are hospitalized or those that may be at high risk for developing complications from the flu. This may include women who are pregnant and those who have compromised immune systems.
Most of the time, a specific diagnosis will not make a difference in how a person is treated. Treatment for the flu consists of rest, drinking plenty of fluids and taking over-the-counter cold/flu and fever reducing medications when necessary. Some people, those that are in the high-risk categories, may require anti-viral medications as well.
"Q&A: Influenza Diagnostic Testing During the 2009-2010 Flu Season." 2009, Sept 29, H1N1 Flu , Centers for Disease Control and Prevention.
"Interim Recommendations for Clinical Use of Influenza Diagnostic Tests During the 2009-10 Influenza Season", 2009, Sept 29, H1N1 Flu , Centers for Disease Control and Prevention.