My last period was jan 10 and i had sex the 31st. how accurate is a negative pregnancy test result? my period has not come yet, thats why i took it.

Too soon, maybe: PG tests are different. Read to take it for the brand you are buying. Make sure you follow instructions accurately. They typically can show pregnancy from 2-7 days after a missed period. But there are exceptions to every rule and if negative but no period, see your doc and consider a blood pregnancy test. You should also see your doc if you are at risk of getting a sexually transmitted disease/

Pregnancy Test: Home pregnancy tests can show positive as early as 3-4 days after implantation. Implantation generally occurs 6-12 days after ovulation. So if the egg was fertilized right at ovulation and you used the most sensitive home test it could be positive at 9 days. On average it is 13-14 days after fertilization/ovulation when it is positive. They are accurate, check again in 4-5 days.