Oh, you live in Seattle? I was just wondering how you were going to get it there.
1) Testing too soon after exposure OR testing after taking too much antiviral therapy. The therapy reduce the amount of virus present and thus the immune system could not detect it.
2) Well, statistically, there are about the same number of each. The stated sensitivity of the test for HSV 2 is 97% which means 3% of negatives are false negatives. On the other hand, about 6% of people who test on the ELISA HSV 2 test, obtain values within the low positive range, which is 1.1 to 3.5. Half of those are false positives. So that makes the false positive rate about 3% as well.
Let me know if you have more questions (you an opt for more at the registration site) when you get your test results back.
Terri