"But if the test is performed correctly, any line no matter how faint is a true positive.". But when I came back to check the test an hour later a positive line had . I took two rapid at-home tests just to be extra sure and then got a PCR test from a testing site so my results could be included in . On day six, about 50 percent will still test positive. What to Know About COVID Tests: Accuracy, Inconclusive Results, Faint "If the test is negative one or two days after symptoms start, then I would maybe think you didn't get a good sample and should test again.". If you have COVID-19 symptoms, test yourself immediately. A faint positive lateral flow test result is shown in the image above Credit: Sun Online. You should also take a test if you're exposed to someone who has COVID-19, the CDC says. But Why? Does a strong, dark line on a COVID-19 rapid test mean you're more infectious than a faint . "The recommendations for serial testing are for people that have been exposed and are trying to diagnose themselves," says Karan. You're sticking a cotton swab up your nose and hoping to snare some virus. For those who test positive for COVID but have no symptoms, day 0 is the day of the . "What . Anyone who provides negative lateral flow tests on day six and day seven will now be able to end their quarantine after seven days. However, if the "positive" line is very faint and appears after a certain amount of time, it could actually mean you are not infected, a doctor . Kristina Kasparian, who works from home in Montreal, believes she may have gotten Covid from her husband, who is a schoolteacher. It is probably worth doing more lateral flow tests in the days following to see if the result becomes stronger. Mar. Lateral flow test. In total, 462 rapid test results, or 0.05 per cent of the 900,000 results, resulted in false positives. When Dr. Jillian Horton, an internal medicine doctor in Winnipeg, started feeling ill, she was pretty sure she had Covid.