COVID-19 Testing Guidance (2024)

FAQs

How likely is a false positive at home covid test? ›

The percentage of rapid antigen tests with false positive results is reported to be less than 1%.

However, a single negative result with an at-home test may not be accurate because you may have taken it before the virus reached detectable levels. That's why, if you're using at-home tests to detect an infection, you should test more than once.

Wait five days to test after exposure if you do not have symptoms. If you have symptoms but test negative, you should test again after 48 hours.

“The less dark, the line is, the less viral material that is present,” he says. “This could reflect diminishing contagiousness, or the start of it.”

Interestingly, ~5% of positive self-collected rapid tests were read by the patient as negative yet were deemed to be positive results by the clinician team when re-read. Conclusion: This study supports that self-collected rapid tests show similar sensitivity and specificity to those performed by clinicians.

Low-grade fever seems to be one of the more common early markers of COVID-19, Kline said, but not everyone will have a fever. Other potential symptoms include muscle aches, headaches, loss of appetite, and loss of taste or smell. Symptoms can appear between two and 14 days after exposure.

If you test negative and have symptoms of COVID-19, test again 48 hours after the first negative test. If you retest, consider asking a health care provider for a molecular test, such as a PCR test, which may provide more accurate results.

When should you test? Test right away. If your first test is negative, test again 1-2 days later. Even if you don't feel sick, test after exposure and again 3-5 days after last exposure.

Many people with COVID-19 get better with rest, fluids and treatment for their symptoms. Medicine you can get without a prescription can help. Some examples are: Fever reducers.

How can I tell if I have COVID or a cold? ›

You may have a runny nose, cough, congestion, and sore throat. But you won't usually have the aches and fever that are common with COVID-19 and flu. Often, you'll feel better in a couple of days. There's no cure for the common cold.

The FLiRT variants is just a technical term for the continued mutation of the Omicron variants of COVID-19. And for the last year or so, pretty much all the variants of COVID-19 that we've seen circulate in the United States have been variants of Omicron.

However, individuals are typically contagious for about 10 days after the onset of symptoms. For those with mild to moderate symptoms, this period can be shorter, often around 5-7 days. For people with severe symptoms or those with a weakened immune system, contagiousness can last up to 20 days.

Isola​​te​ If you test positive, you are strongly encouraged to isolate (stay home and away from other people) for at least 5 full days, to prevent spreading the disease to others. Isolation is recommended even if you have been vaccinated or have had COVID-19 before.

After you have been exposed to COVID-19 or another respiratory virus, it can be especially helpful to use respiratory virus prevention strategies, such as wearing masks, taking steps to improve air flow and filtration, practicing good hand hygiene, cleaning regularly, physical distancing, and/or testing.

There is a chance that this test can give a positive result that is wrong (a false positive result) particularly when used in a population without many cases of COVID-19.

According to the study findings, rapid tests for COVID-19 have a very high specificity (the capacity to detect negative cases/healthy individuals), with a true negative proportion consistently above 98 per cent.

Are COVID-19 tests an effective way to indicate if you're contagious? Not always. PCR tests and antigen tests can detect the virus. However, a positive test doesn't always indicate active contagiousness, and a negative test doesn't always indicate that you're COVID-free.

Results read before 15 minutes or after 30 minutes may lead to a false positive, false negative, or invalid result.