Influenza (the flu) is a viral infection that tends to be seasonal, beginning in late November and disappearing in early spring. It is a common respiratory (affecting the lungs) illness that causes headaches, fever, chills, muscle pains, exhaustion, a stuffy nose, sore throat, and a cough. Symptoms of flu tend to be more severe and longer lasting than the flu-like symptoms caused by the common cold. Flu and its complications can…Influenza (the flu) is a viral infection that tends to be seasonal, beginning in late November and disappearing in early spring. It is a common respiratory (affecting the lungs) illness that causes headaches, fever, chills, muscle pains, exhaustion, a stuffy nose, sore throat, and a cough. Symptoms of flu tend to be more severe and longer lasting than the flu-like symptoms caused by the common cold. Flu and its complications can lead to hospitalisations even death, especially in the very young, the elderly, and in those with lowered immune responses or pre-existing lung disease. There are three types of influenza, known as A, B and C, each of which can change many times to create multiple strains. Influenza virus A is the most common and causes the most severe symptoms. Type B is less common and causes less severe symptoms, whilst type C usually causes only a mild illness (similar to the cold) and is usually not included in influenza tests. Flu testing relies on detecting virus that is being shed in the respiratory secretions of the person infected. Detectable virus is usually only shed for the first few days that a person is ill, so most testing must be done during this time period. Anti-viral medications have been developed to treat either influenza A alone, or both A and B. These medications, if given within 48 hours of the onset of symptoms, can reduce the severity of symptoms and reduce the time that a patient is sick by about a day. (They will not help if given later and they will not work against other viruses or against bacterial infections). These medications will only be prescribed if the person is at particular risk of complications and it is known that influenza A or B are circulating in the community. For otherwise healthy people, the treatment is to stay in bed and rest, drinking plenty of fluids, until the symptoms have cleared up Flu testing is also useful for documenting that the flu (A and/or B) has reached a community, and for identifying outbreaks in particular populations, such as a nursing home, school, or neighbourhood. Identifying these outbreaks can assist healthcare workers in the prevention and treatment of the flu throughout a community. Influenza sub-typing tests are used to determine which sub-type of flu a person has, such as H1N1 (swine flu) or H3N2 which is useful in tracking the spread of flu in a season. How is the sample collected for testing? A nasal swab is collected by having you tip your head back, then a swab (like a long cotton bud) is gently inserted into one of your nostrils until resistance is met (about 1 to 2 inches in), then rotated several times and withdrawn. Sometimes a doctor may use a throat swab in place of or as well as a nose swab. In children, a nasopharyngeal aspirate is often taken instead of a swab, by using a syringe or other suction device to insert and immediately withdrawing a small amount of saline into the back of the nose while the head is tipped back. These procedures should not be painful, but may tickle a bit and cause your eyes to well-up. Collection of a good quality sample is crucial for the flu tests to work well. Influenza virus can also be detected in bronchoalveolar lavage (BAL) fluid which is collected from the lower respiratory tract (lungs) of more seriously ill people. Is any test preparation needed to ensure the quality of the sample? No test preparation is needed. See MoreSee Less
