Your best accuracy to get reliable results from a pregnancy test is doing the pregnancy test after you miss your period.
A: An early urine pregnancy test will not show up positive until there is enough hCG, the pregnancy hormone, in your body. This hormone isn't even present until several days after the fertilized egg implants into your uterus. Implantation happens 6-12 days after you ovulate. It isn't detectable until around the time of your period (some women don't get a positive result until days after a missed period). While other women are able to take an early pregnancy test (like First Response) a couple of days before their period is due and get a positive test. However, that is not the case for MOST women. Have you ever heard of a "false negative"? It's when you ARE pregnant, but get a negative test and then test a few days later and get a positive. That's what happens most of the time when women test before their periods.
First Response (the test that advertises "99% accurate. Our most accurate results 5 days sooner"), says the following regarding it's accuracy: "4 days before your period, the test is 63% accurate; 3 days before your period 83% accurate; one and two days before 93% accurate." So it's most accurate around the time you miss your period.
When you do a pregnancy test too early, you may get a false negative pregnancy test and be disappointed. Waiting until you miss your menstrual period and until your menstrual period is late, maybe 1-2 days late, will save you money and will give you a better chance to prevent a false negative pregnancy test. A healthy mid twenties couple without known fertility problems has a 20% chance each month getting pregnant. 80% will get pregnant within the first year of trying.