The sensitivity of home pregnancy tests is lower than blood pregnancy tests. HPTs can usually detect pregnancy 6-7 days after embryo implantation. In certain cases, it can be detected as early as 2 to 3 days before you miss your period, though rarely.
However, this is variable and in fact can lead to false negatives if the test is taken too early. If your body has not started producing hCG yet, you may get a false negative result.