Fwiw this is pretty fair. The test is a good indicator but not that accurate. If it's positive it's probable (but not certain) that you have had coronavirus but it is showing old infections too. If it's negative it really doesn't mean you're clear as it could just have been done incorrectly or the test was taken at the wrong point in the cycle of development.
As an alternative, if it's 70 percent reliable then the chances of all four tests tottenham had showing positive for orient players ALL being wrong are 0.3 * 0.3 * 0.3 * 0.3 = 0.0081. With those figures there's over a ninety nine percent chance one of those players has the virus. I'm sure they're glad they tested.