The bottom line is that the more often you use the tests the better, said Dr Michael Mina, a Harvard epidemiologist and proponent of rapid tests. (Dr Mina advises Detect, Inc., a diagnostic company working on a rapid molecular test.) If you want to spend time with a medically vulnerable person, you need to take a test a few days before you see them and then take another. test on the day of the visit. “Think about how can I test as closely as possible to what I’m doing? Dr Mina said. “When I go to visit my parents, I always bring rapid tests with me. Just before going through the door, I use the test in my car.
What if the test is positive?
Most of the time, a positive result means you have the coronavirus, especially if you are having symptoms. But false positives do happen. Recently, Ellume, an Australian company, recalled nearly 200,000 test kits over concerns about a higher than expected false positive rate.
If there is reason to doubt a positive result, do another test, preferably at another manufacturer or at a testing center. People who organize large events, like weddings, and use the tests to screen guests should have a few more tests handy from a different brand for guests who test positive. You can be confident in the result if the second test is negative, said Dr Mina.
“It would be really rare for someone to have a true positive and then have a second test show a false negative,” he said. “If you’re having dinner, you might as well cancel dinner if someone is positive.” But if it’s a serious event, like a wedding and theft somewhere, and you’re going to test a few hundred people, you may get a false positive and want to retest.
How do I find a home test?
While supplies are expected to improve in the coming weeks, testing can be hard to come by right now. Try store websites like CVS, Walgreens, Costco, or Walmart, or check with a local drugstore. I recently searched for a friend in New Jersey on the CVS website and found BinaxNow tests in a store about 30 minutes away. When he arrived he found the shelves full of tests.
A word of warning: be sure to search by brand name. If a store is sold out for a quick test, the website may direct you to a different type of test called a home collection test, which requires you to send in the sample to get the result. But wait until you find a quick test. “The fact that they’re fast,” said Dr Gronvall, of Johns Hopkins, is what “makes them a really good test to make sure someone isn’t contagious at that time.”