I believe different HTP brand will detect at different HCG level. You can search online.
On my second IVF, I got negative on other tests, but with clear blue digital, it detect at 25. I got "pregnant" 2 days (12dpo) before beta. When I break the test apart, I see there is a faint line there, and I got beta with 47 which mean it about double in 2 days.
On my third IVF, I do same thing, but I didn't get "pregnant" till 1 day (13dpo) before beta. I also break it apart, also a faint line, not dark as control line. Next day, I got beta at 37 which mean it also about another half in 1 day.
This is just my own experience.
SSBD
HI-
I totally understand. I just went through IVF and happily got a BFP last week. However, I thought I would lose it waiting for my first round of blood work. I refrained from taking a HPT because if you had to take any amount of HCG, which I did 3 different days after transfer, it will register as a positive on your HPT. Ideally that is a true read and you are pregers but I can't imagine anything more disappointing than having your beta HCG done with negative results. The clinic I used told me NOT to take a HPT because the results don't mean anything - or +. I know this is so hard. Hang in there. I am wishing you lots of baby energy. Remember, you are pregnant until proven otherwise : )