HOUSTON – Doctors and government leaders are urging us to get tested for COVID-19 even if we don’t have any symptoms. He answered our questions about which tests are best to detect the virus. A: Varon said rapid tests, even if taken with a nasal swab, have proven to be inaccurate about 20% of the time. Rapid Nasal Swab TestAverage 20% false-negative readingsUsually $150 & upResults come back in as little as 15 minutesSaliva and mouth swab testsAverage 30% chance of false-negative readings. A: It could be because you were given other tests in addition to the COVID test.