Rapid Antigen Testing: When to Test

Testing and Contact Tracing

Here’s the latest scoop on when to test for Omicron with rapid antigen tests:

NOTE:  Be sure to scroll down for more info and resources.

🦠If you’re exposed: Your first positive antigen test could come as early as 2 days or as late as 10 days after exposure. The sweet spot for antigen testing is 3-5 days after exposure. If you only have one test, Day 5 is your best bet.

🤒 If you have symptoms: Your first positive antigen test could come before, during, or after the peak of your symptoms. If you only have one test, wait 2-3 days after symptom onset for your best chances of catching the virus.

🔁 Test test test! Depending on test access, test daily, or every 2-3 days if you have been exposed or have symptoms.

⚠️ A single negative rapid antigen test can’t rule out COVID-19, so please play it safe if you have been exposed or have symptoms.


📈 Rapid tests only work when there is lots of virus present, so you need to time it when the virus has had time to replicate, but has not yet been cleared out. With the Omicron variant, levels of the SARS-CoV-2 virus in nasal swabs peak 3 days after the first positive PCR, or 2-6 days AFTER symptom onset.

Keep Calm and Keep Testing,
Those Nerdy Girls

Thanks to Fueled by Science for this timely post.


When is the Best Time to Test for COVID?

Secondary Attack Rates, Transmission, Incubation and Serial Interval Periods of first SARS-CoV-2 Omicron variant cases in a northern region of Spain.

Outbreak caused by the SARS-CoV-2 Omicron variant in Norway, November to December 2021

Duration of Infectious Virus Shedding by SARS-CoV-2 Omicron Variant–Infected Vaccines

High rate of BA.1, BA.1.1 and BA.2 infection in triple vaccinated

Link to Original FB Post