About 8 years ago, I had a really bad UTI that wouldn't get better with antibiotics. So they tested me for Chlamydia - it came back negative, so they tested me again. Negative again... but they gave me antibiotics for that anyway because they were so sure I had it, and told me to consider that I'd had it for future reference, because sometimes the tests give a false-negative. So yeah, basically, I hope they're a more use now.