Q: I am now 13 DPO and my HPT is negative. This was a really sensitive test. Could I still be pregnant or does a negative test mean I am definitely not pregnant?
A: Even though your HPT was negative, you could still be pregnant and should repeat the pregnancy test in a couple of days. In about 3 in 4 pregnant women, the HPT is positive by 14+ DPO (see more on this HERE) but in 1 in 4 pregnant women it takes longer for the HPT to turn positive.
Based on when you tested during the menstrual cycle there are certain calculated chances of still being pregnant with a negative pregnancy test.
In your case, with a negative HPT on CD 13, there is still about an 9.5% chance that you could be pregnant.
Calculations reflect the following underlying assumptions: