Quantitative Influenza Antibody (Nasal or Throat Swab) (2024)

FAQs

Quantitative Influenza Antibody (Nasal or Throat Swab)? ›

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).

Proper serological testing for diagnosis of influenza requires paired acute and convalescent sera collected 2-3 weeks apart, with reliable testing at a limited number of public health or research laboratories to assess a 4-fold or greater rise in influenza virus strain-specific antibodies.

These tests include reverse transcription polymerase chain reaction (RT-PCR), viral culture, and immunofluorescence assays. All of these tests require that a health care provider swipe the inside of your nose or the back of your throat with a swab and then send the swab for testing.

A positive test result means you may have the flu. It's possible to have a false positive, which means your test says you have the flu, but you really don't. Depending on your health, your provider may prescribe medicine to help prevent the flu from becoming a more serious illness.

In very young children, influenza viruses can be shed for longer periods; therefore, in some instances, testing for a few days after this period may still detect influenza viruses. Immunosuppressed persons may have detectable influenza viruses in respiratory specimens for prolonged periods (weeks to months).

What is this test? This test checks for flu (influenza) antibodies in fluid from your nose or throat. The flu is a common illness of the respiratory system. It can have serious health effects.

A: A positive antibody test result could mean you previously had a SARS-CoV-2 infection or COVID-19. A positive antibody test could also mean the test is detecting antibodies in your blood in response to your COVID-19 vaccine. Not all SARS-CoV-2 antibody tests will detect antibodies in response to a COVID-19 vaccine.

1 Tilt patient's head back 70 degrees. 2 Insert swab into nostril. (Swab should reach depth equal to distance from nostrils to outer opening of the ear.) Leave swab in place for several seconds to absorb secretions.

A rapid antigen flu test (rapid influenza diagnostic test, or RIDT) is the least accurate type of flu test. They have moderate sensitivity (50% to 70%) and high specificity. Sensitivity refers to a test's ability to determine that you have a disease or illness — you're positive for the illness.

Influenza B is a common type of flu virus that causes symptoms like fever, headache, chills, cough, congestion, and body aches. This type of flu is highly contagious. While anyone can develop flu type B, young children and people with underlying health conditions have the highest risk.

How long is influenza contagious? ›

Period of Contagiousness

People with flu are most contagious during the first 3 days of their illness. Some otherwise healthy adults may be able to infect others beginning one day before symptoms develop and up to five to seven days after becoming sick.

Type A influenza is generally considered worse than type B influenza. This is because the symptoms are often more severe in type A influenza than in type B influenza. Type A influenza is more common than type B influenza. Researchers suggest that most adults have considerable immunity against type B influenza.

A positive result means that the RIDT detected influenza viral antigen, but does not necessarily mean viable influenza virus is present or that the patient is contagious.

Note: Not everyone with flu will have a fever. People with suspected or confirmed flu, who do not have a fever, should stay home from work at least 5 days after the onset of symptoms. People with flu are most contagious during the first 3 days of their illness.

Influenza: After close contact with someone who has flu, staying home is not required, unless symptoms occur. Home quarantine means avoiding other people. Home Isolation for Sick People with Symptoms. Home isolation for COVID-19 is required for at least 5 full days or longer.

Even if you try your best to stay healthy when someone in the house has the flu, there's still a chance that you'll become infected. The flu causes symptoms that range from mild to severe, and if you live with certain medical conditions such as heart disease, getting the flu can increase your risk of complications.

A PCR test can detect the genes of the virus or bacteria causing your symptoms. You can also buy over-the-counter rapid antigen tests (RAT) to diagnose the flu at home. Usually, these tests can tell you if you have: influenza A.

Following influenza virus infection or receipt of a flu vaccine, the body's immune system develops antibodies that recognize and bind to “antigenic sites,” which are regions found on an influenza virus' surface proteins.

Reference Range: Influenza A Virus Antibody, IgG: 0.89 IV or less: Negative - No significant level of influenza A virus IgG antibody detected. 0.90-1.10 IV: Equivocal - Questionable presence of influenza A virus IgG antibody detected. Repeat testing in 10-14 days may be helpful.

Antibody testing shows whether you have antibodies to the virus that causes COVID-19, also called coronavirus disease 2019. Having antibodies suggests you've either had an infection with the virus in the past or you've had the COVID-19 vaccine. Antibody testing is not used to diagnose COVID-19.