How long after flu symptoms will you test positive?
The Centers for Disease Control and Prevention (CDC) estimates that between 2010 and 2020, the flu caused between 9 million and 41 million cases of influenza annually; however, this is only an estimate.
The CDC does not know the exact number of flu cases each year for a variety of reasons, including the fact that many individuals do not seek medical treatment for flu symptoms, and even if they do seek treatment, clinicians may not test for the flu because it does not affect how a patient is treated.
The CDC argues that this and other variables (such as people seeking care when their flu cannot be identified by a flu test and the fact that flu is not a reportable condition) contribute to the fact that even the data we have may underrepresent the actual burden of flu in the United States in any given year.
A flu test is the only genuine way to tell whether or not you or a loved one having flu-like symptoms has the flu—and it may be a powerful tool, when reported, to assist scientists in understanding precisely how bad the current flu season is affecting the community. This is especially significant given that COVID-19 is still circulating, as symptoms of the two diseases can be highly similar.
However, obtaining a flu test can be somewhat intimidating—after all, no one likes a swab up their nose—but it is required. What you need to know about flu testing, including who typically needs one, how long it takes to receive results, and what to do if you test positive for influenza
How can you know if a flu test is necessary?
Your need for a flu test will depend on the symptoms you show to your physician and how they diagnose those symptoms. According to the CDC, the most common signs and symptoms are:
- Fever and shivering (note: not everyone with flu will have a fever)
- painful throat
- Runny or stuffy nose
- body or muscle aches
- Fatigue or weariness
- emesis and diarrhea (this is usually more common in children)
You may recognize that the above symptoms are also frequently observed in patients with COVID-19.
How can I tell if I have the flu?
If you have a fever, cough, sore throat, a runny or stuffy nose, body aches, headache, chills, and weariness, you may have influenza (flu). Some individuals may have vomiting and diarrhea, albeit this is more prevalent in youngsters. Influenza can cause respiratory symptoms in the absence of a fever. Typically, influenza viruses cause the most sickness during the winter months.
Nevertheless, influenza can occur outside of the regular flu season. Other viruses can also produce respiratory illnesses similar to influenza. Therefore, it is impossible to diagnose influenza based just on symptoms definitively. Laboratory tests can be performed if your doctor requires conclusive evidence that you have the flu.
What types of influenza tests exist?
Several tests exist to detect influenza viruses in respiratory specimens. The most prevalent are referred to as rapid influenza diagnostic tests (RIDTs). RIDTs function by identifying the viral components (antigens) that elicit an immune response.
These tests can produce answers within 10 to 15 minutes, although they may not be as precise as other influenza testing. Therefore, you may still have influenza despite a negative rapid flu test result. Other flu tests, known as “rapid molecular assays,” detect the virus’s genetic material. Rapid molecular assays produce accurate results in 15 to 20 minutes, whereas RIDTs are inaccurate.
In addition to RIDTs and quick molecular assays, other more accurate flu tests must be conducted in a hospital or public health laboratories. These tests include RT-PCR, viral culture, and immunofluorescence assays. The swab is then sent for testing. Results may take between one and a few hours.
How accurate are rapid tests for influenza?
During an influenza epidemic, a positive quick influenza test is likely indicative of influenza virus infection. However, the capacity of quick tests to detect influenza viruses varies depending on the type of rapid test performed and the type of influenza virus circulating. Also, quick tests detect influenza in youngsters more effectively than in adults.
This diversity in the ability to identify viruses can cause some flu-infected individuals to get a negative quick test result. This is referred to as a false negative test result. Depending on your symptoms and clinical judgment, your healthcare practitioner may diagnose you with influenza despite a negative quick test result.
Can I have influenza and COVID-19 simultaneously?
Yes. It is possible to have influenza and other respiratory disorders, especially COVID-19. Experts in the field of medicine are still investigating the frequency of this condition.
Some flu and COVID-19 symptoms are similar, making it difficult to distinguish between them based on symptoms alone. The results of diagnostic tests can assist in determining whether you have influenza, COVID-19, or another respiratory illness.
Exists a test that detects both influenza and COVID-19?
Yes. There is a test for seasonal influenza A and B viruses and SARS-CoV-2, the virus responsible for COVID-19. U.S. public health laboratories utilize this test for surveillance purposes. Simultaneous testing for these viruses will provide public health professionals with crucial information about how influenza and COVID-19 are spreading and what preventative measures should be taken. Additionally, the test will allow public health laboratories to save time and testing materials and possibly produce test findings more quickly.