If it was a fresh transfer, you should wait at least 2 weeks from the retrieval day so you don't have any hcg from the trigger shot in your system...most people say that it is out of your body within 10 days. I was able to get a faint positive hpt 14 days past ER, or 12 days past a 3 day transfer. If you did a 5 day transfer, you would only have to wait 9-10 days from the transfer.
If it was a frozen, then you should be able to find out within a 2 week span...maybe 10 days? Everyone is different though.
For my 2nd fresh IVF in '06, I got a positive beta but the number was only a 28. My numbers more than doubled and my daughter just turned 16 months!
I never did an hpt, but it probably would have been negative. And, there was a story of a woman who got a negative hpt the morning of her beta and then found out the numbers were in the 400 range. So, sometimes, you can't trust the test.
When is your beta? Good luck!!