Home pregnancy tests have become very reliable, and have improved a great deal in the last decade. If you have ever taken a pregnancy test, you are aware that they work by detecting the level of hCG, human Chorionic gonadotropin, in your urine. Taking a pregnancy test involves peeing directly onto the pregnancy test, or alternatively urinating into a cup and then inserting the pregnancy test into the cup. Whatever is easier for you is best both methods work equally well.
The hormone hCG will start being produced in the female body as soon as implantation has occurred, though hCG levels are very low at first, and will continue rising in the first few weeks of pregnancy. If you are one of those impatient women who just has to know whether they are pregnant or not, taking a pregnancy test right after implantation will give you a shot at getting an accurate answer.
I would advise anyone to hold off until twelve days after ovulation to get the best chances that implantation might actually have taken place. Women who have noticed an implantation bleeding could already take a pregnancy test the day after the bleeding was observed. As any home-pregnancy test manufacturer will tell you though, the best results are still achieved on the day after a missed period. That does not mean that you cannot take a pregnancy test earlier than that, but it does mean that a negative pregnancy test taken during the luteal phase of your cycle may not be accurate. But, if your pregnancy test does turn up positive, you are almost definitely pregnant!