According to the ClearBlue pregnancy test accuracy results they are: 4 days before expected period= 51% accurate 3 days before expected period= 82% accurate 2 days before expected period= 90% accurate 1 day before expected period =95% accurate the day of expected period =99% accurate To ensure the best results: * Take the test in the morning, if possible, because your hCG (pregnancy hormone) levels are at it's highest * Don't drink a bunch of fluids before taking the test because it will dilute your urine and can affect the results * Take the test no more than 1 day before expected period. Although some test say that you can see results up to 5 days before your missed period, the percentage of accuracy is very low. * urinate for as long as possible on the foam-like strip * Check the results in the window frame of time suggested by the instructions of the pregnancy test.