Tuesday, March 21, 2023

How Do They Test For The Flu

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Will My Health Care Provider Test Me For Flu If I Have Flu

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While your doctor may test you for flu, not everyone who goes to the doctor with flu-like symptoms will be tested. After evaluating you, your doctor may choose to diagnose you with flu without the need for testing based on your symptoms and his or her own clinical judgement.

Please visit diagnosing flu for more information.

Comparison Of Rapid Test Results To Rt

Eighty-five of the 200 samples processed for RT-PCR were positive for influenza virus: 21 for influenza virus A and 64 for influenza virus B. Directigen detected virus in 63 specimens confirmed to be positive by RT-PCR but did not detect virus in 16 samples with positive RT-PCR results . Among the 16 specimens with indeterminate results by Directigen, 6 were positive by RT-PCR . Two samples positive by Directigen gave negative results by RT-PCR.

QuickVue detected influenza virus A in 18 samples and influenza virus B in 54 samples found to be positive by RT-PCR but did not detect virus in 12 samples positive by RT-PCR . One sample positive for influenza virus A by RT-PCR gave an invalid result by QuickVue. Eleven samples were positive by QuickVue but negative by RT-PCR.

When Do I Need A Flu Test

If you have flu-like symptoms or are concerned about possibly having the flu, talk to your healthcare provider. Most people dont need a flu test and recover from the flu within a week or two, but a number of factors can contribute to your provider wanting you to get a flu test.

Symptoms of the flu include:

  • Sudden onset of moderate to high fever.
  • Being over the age of 65 or under the age of 5.
  • Being in the hospital for treatment for another condition.

You may also need to take a flu test so that public health officials or providers can figure out whether an outbreak of respiratory illness in a community, such as a school or nursing home, has been caused by the flu.

Public health officials and providers may also use specialized flu tests to identify the type of flu virus thats causing infections.

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Is It Too Late To Get A Flu Shot

If it turns out you dont have the flu, and you havent received your flu shot, then you can get one on the spot. To schedule your flu shot and/or COVID-19 vaccine or booster at a CVS Pharmacy or MinuteClinic nearest you, visit cvs.com or use the CVS Pharmacy App.

Schedule your flu and COVID-19 vaccines today! These vaccines are an important way to protect yourself and your loved ones from serious illness.

Is There A Test Than Can Check For The Flu And Covid

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Yes, there are at-home and laboratory tests that can check for influenza type A and B viruses and SARS-CoV-2, the virus that causes COVID-19, at the same time.

Some of the symptoms of the flu and COVID-19 are similar, so it can be hard to tell the difference between the two illnesses. If you have symptoms of the flu and/or COVID-19, contact your healthcare provider as soon as possible. Theyll likely recommend diagnostic testing, which can help determine if you are sick with the flu, COVID-19 or another respiratory infection.

A note from Cleveland Clinic

A flu test is a simple test your healthcare provider can perform on you or your child. While most people dont need a flu test and recover from the flu within a week or two, certain factors can contribute to your provider wanting you to get a flu test. If you have any questions or concerns, feel free to reach out to your provider. Theyre available to help.

Last reviewed by a Cleveland Clinic medical professional on 04/13/2022.


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Can I Have Flu And Covid

Yes. It is possible to have flu as well as other respiratory illnesses including COVID-19 at the same time. Health experts are still studying how common this can be.

Some of the symptoms of flu and COVID-19 are similar, making it hard to tell the difference between them based on symptoms alone. Diagnostic testing can help determine if you are sick with flu, COVID-19, or another respiratory infection.

How Accurate Is The Rapid Flu Test

Rapid influenza diagnostic tests accurately detect the presence of the flu virus antigen between 50% to 70% of the time and are better at detecting influenza A than influenza B. Some modifications to the test can increase accuracy to about 80% this increased accuracy is now required by the Food and Drug Administration .

In practical terms, this means if 10 people with the flu were tested, the test would miss two to five of those and falsely report that they did not have the virus. This is known as a false negative result. RIDTs are not the preferred method of testing due to the high likelihood of these false negative results.

The RIDTs, if positive for influenza, are pretty accuratemeaning if the test is positive, the chance you have influenza is great. Roughly 1 out of 10 tests will result in a false positive, which for a test done in the office in 15 minutes is very good. A false positive is less likely to occur during flu season and more likely to occur outside of flu season when fewer people have the flu.

Compare accuracy of rapid flu tests

Rapid molecular assay tests tend to be more accurate than RIDTs, with a 90 to 95% likelihood that the test will detect the virus in those who have the flu. Using the example above, if you have 10 people who have the flu, the RIDT may miss anywhere from two to five of those diagnoses, but the molecular assay would miss only one, if any.

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How Is Influenza Diagnosed

It is hard to know for sure you have the flu on based on symptoms alone. A doctor’s exam may be needed to tell whether you have developed the flu or a complication of the flu. If you develop flu-like symptoms and are concerned about your illness because you are at high risk for complications or any other reason, you should talk to your healthcare provider. There are tests that can determine if you have the flu as long you are tested within the first two or three days of illness and many providers use antiviral medications when they are confident of the diagnosis.

A Claim That Started In The Us Which Suggests That A Case Of Cold Or Flu Or A Previous Vaccine Against Them Can Give A Positive Covid

Flu test can produce false negatives

A CLAIM THAT a person with a cold or flu will test positive for Covid-19 has surfaced in Ireland in recent days after starting in the US.

The claim, which has appeared in several forms on social media, centres on an argument that conflates antibody testing for previous Covid-19 infections with viral testing for an existing case of Covid-19.

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What Factors Can Affect The Results Of Flu Vaccine Efficacy And Effectiveness Studies

The measurement of flu vaccine efficacy and effectiveness can be affected by virus and host factors as well as the type of study used. Therefore, vaccine efficacy/effectiveness point estimates have varied among published studies.

Virus factors

The protective benefits of flu vaccination are generally lower during flu seasons where the majority of circulating flu viruses differ from the flu viruses used to make the vaccines. Flu viruses are continuously changing through a natural process known as antigenic drift. However, the extent of antigenic drift and the number of drifted viruses in circulation can vary for each of the four viruses included in the seasonal flu vaccine. So even when circulating flu viruses are mildly or moderately drifted in comparison to the vaccine, it is possible that people may still receive some protective benefit from vaccination and if other circulating flu viruses are well matched, the vaccine could still provide protective benefits overall.

Host factors

In addition to virus factors, host factors such as age, underlying medical conditions, history of prior flu illness and prior flu vaccinations can affect the benefits received from vaccination.

Study Design Factors

Factors Related to Measuring Specific versus Non-Specific Outcomes

How Do I Know If I Have Flu

Your respiratory illness might be influenza if you have fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and/or fatigue. Some people may have vomiting and diarrhea, though this is more common in children. People may be sick with flu and have respiratory symptoms without a fever. Flu viruses usually cause the most illness during the colder months of the year. However, flu can also occur outside of the typical flu season. In addition, other viruses can also cause respiratory illness similar to flu. So, it is impossible to tell for sure if you have flu based on symptoms alone. If your doctor needs to know for sure whether you are sick with flu, there are laboratory tests that can be done.

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What Do The Results Mean

A positive result means you may have the flu. Your health care provider may prescribe medicine to help prevent flu complications. A negative result means you likely don’t have the flu, and that some other virus is probably causing your symptoms. Your health care provider may order more tests before making a diagnosis. If you have questions about your results, talk to your health care provider.

Learn more about laboratory tests, reference ranges, and understanding results.

What Is The Flu

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Influenza is an acute respiratory illness caused by influenza A or B viruses that routinely spreads through the U.S. during the winter months. Frequent symptoms include fever, headache, fatigue, muscle aches, sore throat, cough, congestion, chills, and a runny or stuffy nose. While this respiratory infection can be mild for many, it is serious and even life-threatening for some. Those most at risk for severe complications are young children, older adults, pregnant women, those with chronic health conditions, or those with weakened immune systems. Many people diagnose themselves with the flu and manage the illness at home with over-the-counter pain relievers. However, getting a flu test and a prescription antiviral medication can reduce the severity and length of your symptoms.

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What Are The Different Types Of Influenza

Influenza viruses are divided into three types designated as A, B, and C:

  • Influenza types A and B cause epidemics of respiratory illness that occur yearly during the winter. They often lead to increased rates of hospitalization and death. Public health efforts to control the impact of influenza focus on types A and B. One of the reasons the flu remains a problem is because the viruses actually change their structure regularly. This means that people are exposed to new types of the virus each year.
  • Influenza type C is more infrequent and causes either a very mild respiratory illness or no symptoms at all. It does not cause epidemics and does not have the severe public health impact of influenza types A and B.

Influenza viruses continually change , which helps the virus to evade the immune system of both children and adults. People can get the flu no matter what their age. The process works like this:

  • A person infected with an influenza virus develops antibodies against that specific virus.
  • The virus changes.
  • The “older” antibodies no longer recognize the “newer” mutated virus when the next flu season occurs.
  • The person becomes infected again.
  • The older antibodies can give some protection against recurrence of the flu. In addition, the flu vaccine given each year is produced from influenza virus strains expected to cause that year’s flu outbreak.

    Labcorp Receives Emergency Use Authorization For At Home Collection Kit For Combined Covid

    BURLINGTON, N.C., Oct. 1, 2021 Labcorp , a leading global life sciences company, today announced that it received Emergency Use Authorization from the U.S. Food and Drug Administration for a combined home collection kit that detects COVID-19 and influenza A/B simultaneously in individuals as young as 2 years of age. The kit will be available at no upfront cost to those who meet clinical guidelines, which may include experiencing symptoms, being exposed to someone with COVID-19 or if asked to be tested by a health care provider.

    Our newest home collection kit makes it convenient for individuals, including children over the age of 2, to take the test in the safety of their homes, said Dr. Brian Caveney, chief medical officer and president, Labcorp Diagnostics. In time for flu season, the single test helps doctors and individuals make more informed treatment decisions given that symptoms of COVID-19 and flu are similar.

    Individuals infected with COVID-19 and flu may experience similar symptoms such as fever, runny and/or stuffy nose and cough. The kit helps people test for both flu and COVID-19 in the safety of their home and avoid the risk of spreading the virus to others. The kit uses a short nasal swab that is inserted into the lower nostril, making it more comfortable and easier for individuals and parents to collect samples at home.

    About Labcorp


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    Flu Testing And Diagnosis

    Influenza is a viral respiratory illness that affectsmillions of people each year.

    Symptoms can include fever, cough, stuffy or runny nose, sorethroat, headache, chills and fatigue. A flu test is not always neededto diagnose the flu. However, in some cases, your health careprovider may need to confirm if you have the flu, so they mayrecommend testing.

    Can You Tell If Its The Flu Or Covid

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    As the flu season ramps up this fall and winter, every cough and sniffle will carry an extra worry: possible COVID-19 infection.

    With influenza, COVID-19, and the usual cold-weather respiratory infections in circulation, experts say its bound to be a confusing season for people to sort out what to do when they fall ill.

    We talked to UC San Francisco emergency care physician Jahan Fahimi, MD, and infectious disease specialist Peter Chin-Hong, MD, about the differences between flu and COVID-19, when to get a test, and why you shouldnt try to diagnose yourself.

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    Is There A Test That Can Detect Both Flu And Covid

    Yes. There is a test that will check for seasonal flu type A and B viruses and SARS-CoV-2, the virus that causes COVID-19. This test is being used by U.S. public health laboratories for surveillance purposes. Testing for these viruses at the same time will give public health officials important information about how flu and COVID-19 are spreading and what prevention steps should be taken. The test will also help public health laboratories save time and testing materials, and to possibly return test results faster.

    The Food and Drug Administration has given CDC an Emergency Use Authorizationexternal icon for this new test. Initial test kits were sent to public health laboratories in early August 2020. CDC will continue to manufacture and distribute these kits.

    More information for laboratories is available.

    How Well Do Flu Vaccines Work During Seasons In Which The Flu Vaccine Is Not Well Matched To Circulating Flu Viruses

    As described above, when the virus components of the flu vaccine are not well-matched with circulating flu viruses, the benefits of flu vaccination may be reduced. However, the extent of antigenic drift from vaccine viruses and the proportion of circulating drifted viruses varies each season. As a result, even when circulating flu viruses are mildly or moderately drifted in comparison to the vaccine, it is possible that people may receive some protective benefit from flu vaccination. Even if some circulating flu viruses are significantly drifted, it is possible for other flu viruses in circulation to be well-matched to the vaccine. It is not possible to predict how well the vaccine and circulating strains will be matched in advance of the flu season, nor is it possible to predict how this match may affect vaccine effectiveness.

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    How Accurate Is A Rapid Flu Test

    A rapid antigen flu test is the least accurate type of flu test. They have moderate sensitivity and high specificity.

    Sensitivity refers to a test’s ability to determine that you have a disease or illness youre positive for the illness. The specificity of a test is its ability to determine that you dont have a disease or illness youre negative for the illness.

    A highly sensitive test means that there are few false-negative results, meaning fewer cases of illness are missed. Since a rapid flu test has moderate sensitivity, its more likely that itll have a false-negative result and miss positive cases. High specificity means that false-positive results are rare.

    How Accurate Is The Flu Test

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    Accuracy of the flu test depends on which kind of test isperformed and the type of influenza thats going around. While RIDTsare the most common flu tests, they are not as accurate as othertypes of flu tests, but they seem to be better at detecting the fluin children than adults. In general, if you receive a positive rapidtest during a flu outbreak, it likely means youre infected with theflu. Note that false negative and false positive test results can occur.

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    What You Need To Know About Dual Covid

    Yes, it is possible to have both viruses at the same time.

    Both diseases can spread from close contact with someone who is infected. The viruses travel through droplets from talking, sneezing, or coughing. Physical contact can also cause infection. Covering your mouth and nose , washing hands regularly, and keeping your distance from others is the best way to prevent the spread.

    Both conditions can spread before the symptoms appear. If you have been in contact with someone who might have the flu or COVID-19, it is important to know that flu symptoms take about 4 days to appear and COVID-19 symptoms take between 2 to 14 days to appear.

    COVID-19 is considered more contagious by the CDC however both are highly contagious viruses. Covering your mouth and nose , washing hands regularly, and keeping your distance from others is the best way to prevent the spread. Additionally, the flu remains contagious up to 7 days after symptoms appear, while COVID-19 for up to 10 days.

    Older adults, pregnant women, and people with underlying medical conditions are at risk of severe difficulties from both COVID-19 and the flu. Children and infants are at a higher risk for flu complications than COVID-19. However, children infected with COVID-19 are more vulnerable to rare complications like Multisystem Inflammatory Syndrome. Vaccines are available for both COVID-19 and the flu.

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