Honestly, I had three lab tests that came back negative. However, I started herbs before the tests. So I always wonder if it is because I started the herbs. I can see the parasites clearly now because I'm really killing them. But I wondered if I had made them just sick enough not to produce eggs with the herbs before the tests.
So, I would wait, but I would ask for 3 tests THREE DAYS IN A ROW! That is the way it is supposed to be done. Then start on the herbs while you wait for the results.