COVID-19 Testing (2024)

FAQs

Can I test negative after 3 days of COVID? ›

One study from researchers at Johns Hopkins suggested that COVID-19 PCR tests conducted 3 to 5 days after a person is exposed that return a negative result shouldn't be relied on alone to gauge infection status, and that in addition, the clinical and epidemiologic situation should be carefully evaluated by health ...

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.

Antigen tests can give false positive results. If you do not have symptoms but you receive a positive antigen result, your health care provider may recommend a molecular test to confirm the result.

If your COVID-19 test is negative

If you have symptoms: You may have COVID-19 but tested before the virus was detectable. You may have another viral infection or illness. Take actions to help protect yourself and others from health risks caused by respiratory viruses.

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.

“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.”

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.

Isolate for at least 5 full days after your symptoms start, or after your first positive test date if you don't have symptoms. Ending isolation: You can end isolation after 5 days if you test negative (use an antigen test) on Day 5 or later – as long as you do not have a fever and your symptoms are getting better.

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.

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 accurate are home COVID tests? ›

The sensitivity of clinician and self-collected rapid testing was very good and relatively similar at 88.2% (clinician) vs. 83.9% (patient); notably, sensitivity was much lower in asymptomatic cases (63% [clinician] vs. 52% [self]) as compared to symptomatic cases (90% [clinician] vs. 88% [self]).

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.

Carr recommends testing five or six days after exposure so the virus has built up enough for detection. It is also possible that a person may be infected and even be symptomatic, but they might test negative simply because the virus has predominantly infected their throat or lungs rather than their nasal cavity.

Most people get better from COVID-19 within 3 weeks. Some people get worse again after they first start to feel a bit better.

If your antigen test (such as an at-home test) result is positive, you may still be infectious. Continue wearing a mask and wait at least one day before taking another test.

In their research on long COVID, the scientists found COVID antigens in the blood for up to 14 months after infection, and in tissue samples for more than 2 years after infection.

"People are having symptoms for one to three days with negative tests, and then they'll turn positive after a few days with the COVID testing. And that was not happening with prior variants." The delayed positivity means it's more difficult to fully trust a negative test result, especially in the first few days, Dr.

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.