In order for a test to be accurate, you need to give your body enough time to make enough antibodies to show up on
a test. In the general population (over 99%), it takes up to 6 weeks to produce
a detectable amount of antibodies (for some people, it takes even less time). There is, however, a small percentage of people (<1%) who have weak immune systems from things such as chemotherapy, autoimmune diseases, and from being on immunosuppressant drugs (i.e.