COVID-19 has sickened millions of Americans and claimed the lives of more than 150,000. At this point, its relentless spread can feel inevitable, especially when we so not know the long term effects this novel coronavirus will have on us. Diagnostic tests identify who is actively infected with the coronavirus that causes COVID-19 because in many cases, people are indeed carrying the virus but show no symptoms. So should you get a test? A positive result, indicating that you are infected with SARS-CoV-2, is very reliable, while a negative result is less certain. You should get tested if you have symptoms of a COVID-19 infection: fever, cough, shortness of breath, chills, muscle pain, new loss of taste or smell, vomiting or diarrhea, or a sore throat. If you don’t have symptoms, public health authorities generally recommend testing if you came in direct contact with someone infected with the SARS-CoV-2, the virus that causes COVID-19, or if you live or work in an environment with known COVID-19 cases. If you have symptoms and test positive, you almost certainly have COVID-19. To avoid infecting others, stay home and away from other people for at least 10 days after your symptoms first appear. After that, you can likely be around others as long as you are feeling better and haven’t had a fever in 24 hours—but check with your doctor first. If you have symptoms and test negative, it’s unclear whether you have COVID-19. Your healthcare provider may test you for other infections and repeat the coronavirus test. If you have two negative tests at least 24 hours apart, it's okay to be around others as long as you are free of fever and symptoms have improved. If a second test is positive or if you are not retested, follow the 10-day rule. If you don’t have symptoms and test positive, it’s likely you’ve been infected with SARS-CoV-2. Even if you don’t develop symptoms, you should stay home for 10 days or until you have two negative tests at least 24 hours apart. If you don’t have symptoms and test negative, you probably are not infected. But given that the test can be falsely negative, if you had close contact with someone with COVID-19, you should still stay home for 14 days to limit the risk of infecting others. To protect yourself and everyone else, once you’re cleared to go out, you should still follow the CDC’s advice to stay home as much as possible and, when you do go out, wear a mask and keep at least 6 feet away from others.