The best time to test for COVID-19 after symptoms begin is immediately once symptoms appear. Testing right away helps confirm if the symptoms are due to COVID-19 so that appropriate steps such as isolation or treatment can be taken. If an antigen test is negative but symptoms persist, it is recommended to take another antigen test 48 hours later to confirm the result, as initial negative antigen tests may not always be accurate early in an infection. For those exposed but asymptomatic, testing is advised at least 5 full days after exposure. In summary:
- Test immediately when symptoms first appear.
- If negative on an antigen test but symptoms continue, retest in 48 hours.
- For asymptomatic exposed individuals, test after 5 days of exposure.
- Molecular tests (PCR) can also be used and are generally more accurate.
- Waiting 2 days after symptom onset for a single test may increase detection accuracy, but testing immediately is still advised with retesting if negative.
This ensures early detection, proper care, and helps prevent spread to others.
