The Clear & Simple pregnancy Test measures the presence of the hormone human chorionic gonadotropin (hcg) in human urine for early detection of pregnancy. In a woman who is not pregnant the hormone hcg (human chorionic gonadotropin) is normally present in urine at very low levels (typically 5Miu/ml). when you are pregnant the body produces much more of this hormone. At the time of the first missed period the level of hormone is detectable by this test. Our test detects hcg in urine at a level of 20Miu/ml. You can test as early as 4 days before the expected date of your period.