This test identify the presence of influenza A and B viral nucleoprotein antigens in respiratory specimens, and display the result in a qualitative way (positive vs. negative).
Influenza, also known as the flu, is a respiratory disease caused by infection with the influenza type A, B, C or D virus. Influenza viruses are spread among people primarily through airborne droplets released when you talk, cough, or sneeze.
The flu is a common disease that is believed to affect around 8% of people in any given year. Flu viruses tend to spread more frequently during colder months and can lead to local seasonal epidemics. Much less often, new strains of flu spread rapidly across the world and cause a pandemic.
The flu can cause a wide range of symptoms including:
- Runny nose
- Sore throat
- Head and/or body aches
For most people, flu symptoms are mild and short-lived. In others, though, the flu can cause life-threatening complications. Children, older adults, pregnant women, and people with certain coexisting medical problems are at a higher risk of serious complications from an influenza virus infection.
There are multiple types of influenza viruses that can cause the flu. Influenza A and influenza B are the only types of influenza that can cause seasonal flu epidemics. An epidemic is a disease outbreak that occurs within a specific geographic area.
Influenza A viruses are classified into many subtypes based on specific proteins on the surface of the virus. As influenza viruses circulate, they undergo genetic changes that can affect their infectiousness and severity. Although uncommon, emergence of a new strain of influenza A can cause a flu pandemic. A pandemic is a global disease outbreak.
Influenza C is far less common and generally only causes mild symptoms while influenza D viruses primarily affect cattle.
A flu vaccine is developed every year based on the strains of influenza viruses that are expected to be circulating most widely in the colder months. Vaccination can reduce the impact of the flu but is not 100% effective. As a result, diagnosis and treatment of influenza can be important for many people.
It is important to note that "the flu” refers only to illnesses caused by an influenza virus infection. While some people may casually use the term "stomach flu” or refer to any condition with respiratory symptoms as a flu, these are inaccurate uses of the term.