Have you had an HPV test with your annual Pap test?
I recently found out that the Pap test misses women with precancerous cells 15-50% of the time. Combining the HPV Test with the Pap for women over 30 increases accuracy to nearly 100%.
Here's a quick clip about the test. You can ask for it along with your pap-- you don't have to do anything extra.
http://www.youtube.com/watch?v=624S8eU_95U