Many pregnancy tests can be taken as early as the first day of your missed period (approximately 14 days after conception has taken place) and be fairly accurate in detecting pregnancy. Some tests claim to be accurate even earlier, although the longer you wait to take the test, the more accurate the result will be, since pregnancy tests detect the presence of human chorionic gonadotropin (hCG) in your urine and hCG levels typically double about every 2 days. It's best to wait until your period is at least a day or two late.
Pregnancy tests aren't foolproof, therefore a negative result doesn't necessarily indicate you're not pregnant. If you get a negative result, but your period is late and you have pregnancy symptoms, you should talk to your doctor. He or she may order a blood pregnancy test, which is more accurate. A positive pregnancy test is a very good indication that you are, in fact, pregnant. There are a few very rare instances in which a false positive is possible, especially if you fail to read the test result in the time the directions specify or if you take medication which contain human chorionic gonadotropin (hCG).
