When the directions on the packet are followed accurately, home pregnancy test accuracy is very close to 100%. The time that a pregnancy test is done is the most crucial factor to getting an accurate result. The most commonly asked question by women who are trying to get pregnant is “How soon can I do a pregnancy test?”

The correct timing depends on two factors - when you ovulated and if and when a fertilized egg implanted in the endometriosis. Pregnancy test accuracy also depends on the particular brand of test kit that you are using, and how sensitive it is to the hCG hormone. This is the pregnancy hormone that all pregnancy test kits are designed to detect. Test kits that are very sensitive will be able to detect the hCG hormone in minute amounts in your urine.

To be able to understand about pregnancy tests, it is important to know what happens after ovulation. The ovary releases an egg, which drops into the fallopian tube; this is the process referred to as ovulation. The egg can only survive for up to twenty-four hours, unless it is fertilized. The best chance of an egg being fertilized occurs when sperm are already present in the fallopian tube. As sperm can live for up to seventy-two hours or longer, they are able to survive in the tube while waiting for an egg to drop.

After fertilization, the egg slowly moves down the fallopian tube, taking several days to make this short journey, and dividing into a multi-celled zygote. When it reaches the uterus, it will implant into the wall (endometriosis), and this is when the body becomes aware that conception has taken place. Before this time, the pregnancy hormone has not been produced and therefore cannot be detected by a test kit; neither are there pregnancy symptoms until the egg has implanted.

It can take anything from three to ten days for the fertilized egg to implant into the thickened wall of the uterus, but the average is about five to seven days after ovulation has occurred. When the egg has attached to the uterine wall, the corpus luteum receives a message to retain the thickened lining of the uterus and the production of the hCG hormone commences. The hormone can first be detected in the blood and urine 24 to 48 hours after it implants.

The amount of the hCG hormone is very low at first, but doubles in quantity each day. It is this hormone that produces the symptoms of pregnancy, so you probably won’t feel any symptoms until around the time your period was due. A sensitive test kit may be able to detect the presence of the pregnancy hormone as soon as seven days after ovulation, but it is more common at about nine or ten days; less sensitive kits won’t produce a result until twelve to fourteen days.

So, you now know that the accuracy of home pregnancy test kits depends on the sensitivity of the brand you use, and how many days the fertilized egg takes to reach the uterus and implant. There is no way of accurately knowing when the implantation takes place, although some women do experience early pregnancy symptoms. To be assured of the best pregnancy test accuracy, wait until the day your period was due, before you do a pregnancy test.