The first day of my last period was on the 28th. I had unprotected sex on the third. I took a pregnancy test on the 11th. The result was negative. How long should I wait for an accurate result?

If your periods are normally every 28 days, then you will ovulate on Day 14. With that in mind, you would ovulate on the 10th. Again, if your periods occur every 28 days, your next period would be on the 25th. The home pregnancy test will detect pregnancy on or about the time for your next period. I would wait and see if your period starts on time. If it does, then obviously you are not pregnant. If it doesn’t, then repeat the pregnancy test.