According to the search results, the First Response Early Result pregnancy test can detect the pregnancy hormone (hCG) at a level of 6.3 mIU/mL, which is estimated to detect greater than 95% of pregnancies on the day of missed period. The same test can detect hCG levels as low as 6 mIU/mL, but only about half the time. In laboratory testing, First Response detected the pregnancy hormone levels in >99% of pregnant women, 3 days before their expected period. However, it is important to note that some pregnant women may not have detectable amounts of the pregnancy hormone in their urine on the day they use the test, and the amount of pregnancy hormone increases as the pregnancy progresses.