If you're willing to be patient, and don't need an answer ASAP, there's always the ultrasound. An ultrasound can show the gestational sac as early as three weeks after conception (the fifth week of the pregnancy). Using a transvaginal ultrasound, the gestational sac can be detected up to a week earlier. The fetus itself can usually be detected a week later, and the fetal heartbeat, while not audible on a fetal doppler, can be seen as a flutter on the ultrasound around 6.5 weeks into the pregnancy. While there is delay compared to when a dip-stick style test could detect the human Chorionic Gonadotrophin (hCG) hormone, which might be able to detect the hCG during the second week of the pregnancy (almost a week before the expected period), it is very reliable.
If a dip-stick method detects a pregnancy, the next step is usually an ultrasound anyway. The process of scheduling an ultrasound, especially with the way some insurances work, it's likely that the time-frames will be right for detecting the gestational sac, at least. As a side benefit, there's nothing quite so reassuring as seeing the flutter of the fetal heartbeat on the screen while they're doing the ultrasound, and most technicians will also print out a copy of "baby's first picture" for you. A dip-stick test offers no such benefits.