Test 5 days before missed period (Testing Early: The one step pregnancy test can be used as early as 5 days before your missed period, which is 4 days before your expected period. The amount of pregnancy hormone increases rapidly in early pregnancy. In clinical testing with early pregnancy samples, the one step pregnancy test gave the following results: Number of Days Before Missed Period: -5 days; 74% of samples from pregnant women getting a pregnant result. Number of Day Before Missed Period: -4...