H1N1 is a type of influenza A virus, which causes different respiratory symptoms, including fever, coughing, sore throat, headache, and fatigue. As these symptoms can also occur with other respiratory infections, laboratory testing may be recommended in certain cases to confirm an H1N1 infection.
H1N1 caused the 2009 influenza pandemic and continues to circulate as a seasonal influenza virus. When laboratory confirmation is required, LifeCell H1N1 Detection by RT-PCR, using nasal/oral swab samples, uses molecular testing to detect the virus. Understanding when testing may be recommended, how the sample is collected and how the timing of testing can affect results can help you better understand the testing process.
What is H1N1?
H1N1 is a subtype of influenza A virus.²It can cause flu-like symptoms such as fever, cough, sore throat, headache, muscle aches, fatigue and a runny nose. ¹ A cough may last for up to two weeks.
Symptoms can vary from person to person, and not everyone will experience all of them. Since these symptoms can also occur with other respiratory infections, symptoms alone cannot confirm an H1N1 infection.
When is an H1N1 Test Needed?
Testing for People at Higher Risk
People at higher risk of influenza-related complications, including older adults, infants, pregnant women and those with certain underlying health conditions, may require medical assessment and, in some cases, influenza testing.
Testing in Hospital Settings
Influenza testing may be particularly important for people admitted to hospital with suspected influenza or acute respiratory illness, such as pneumonia. Clinical guidelines recommend molecular testing in these cases.
For people with severe lower respiratory tract illness, a lower respiratory tract sample may be tested if an upper respiratory sample is negative but influenza is still suspected.
What is an H1N1 RT-PCR Test?
RT-PCR (reverse transcription polymerase chain reaction) is a molecular test for detecting the influenza virus RNA from respiratory samples. It can accurately detect influenza, and some molecular tests can specifically identify influenza A(H1N1)pdm09.
However, this depends on the specific test used. Not all molecular influenza tests will be able to differentiate the H1N1 strain; some can only differentiate between influenza A and influenza B. This means that the laboratory test specifications are important if H1N1 testing is needed.
What Does an RT-PCR Result Detect?
A positive RT-PCR result means influenza viral RNA was detected in the respiratory sample. It does not, by itself, confirm that the virus is actively replicating or that the person is infectious.
A negative result means the target viral RNA was not detected in the sample. However, it does not completely rule out influenza, as results can be affected by factors such as timing of sample collection and specimen quality.
How Is an H1N1 Test Performed?
Nasal and Throat Swab Collection
An H1N1 test typically uses a respiratory sample collected with a sterile swab by a trained healthcare professional. Depending on the test and clinical situation, the sample may be collected from the nose, throat, or both, including nasal, mid-turbinate or nasopharyngeal sites.
H1N1 Testing and Antiviral Treatment
Testing can help confirm influenza infection, but antiviral treatment does not always need to wait for laboratory confirmation. For people who are hospitalised, have severe or progressive illness, or are at higher risk of complications, treatment may be started based on clinical assessment when influenza is suspected.
Therefore, an H1N1 test is one part of the overall clinical assessment and does not by itself determine whether antiviral treatment is needed.
When laboratory confirmation is required, LifeCell H1N1 Detection by RT-PCR, using nasal/oral swab samples, uses molecular testing to detect influenza viral RNA in respiratory specimens.
Conclusion
H1N1 testing can help confirm influenza A(H1N1)pdm09 when laboratory confirmation is clinically appropriate. RT-PCR and other molecular tests detect influenza viral genetic material, while the ability to identify specific influenza A subtypes depends on the test used.
Testing may be particularly useful when the result could influence clinical management, infection control or further evaluation, especially in people at higher risk of complications or those requiring hospitalisation.
The test result should be interpreted alongside symptoms, exposure history, timing of illness and clinical assessment. Specimen type and timing of collection can also affect test results.