ONE STEP pregnancy test detects raised levels of hCG hormone (human chorionic gonadotropin) in urine. The hCG hormone is commonly referred to as pregnancy hormone and its levels >10mIU/ml can indicate pregnancy. Early Detection Pregnancy Test is ultra-sensitive and can detect the presence of the hormone up to 6 days earlier than the day of your expected period, provided that the levels are >25mIU/ml. The amount of pregnancy hormone produced by individual woman varies and in some cases you can test up to 6 days earlier than your expected period, however most certain results are obtained on or after the day of your missed period.