digital tests are about as accurate as the regular ones really. they are just easier to read. The best way is through a blood test from your doctor. but even two weeks after conception is pretty hard....i mean typically you get pregnant around 14 or so days after the 1st day of your period...then it takes a good week or so for the fertilized egg to make it down and implant in your uterus and then it starts making the hormone the regnancy tests detect...and there has to be enough of the hormone in your system for it to make a test respond. That is why most people find out they are pregnant around 4-6 weeks...
You should go to
PeeOnAStick.com it is a lot of fun and provides useful info. good luck!!