HCG Urine pregnancy test measures the presence of the hormone Human Chorionic Gonadotropin (HCG) in human urine for detection of pregnancy. The concentration of HCG in a non-pregnant woman is low, typically around 5 mIU. During pregnancy, much more of this hormone is produced and the Clear and Simple Pregnancy Midstream Test is sensitive to 20 mIU of HCG. The test is capable of detecting pregnancy as early as 4 days before the date of your missed period. However, we do recommend that if you are testing early, that you use the first urine of the day as this is when the HCG hormone is most concentrated.