hCG Midstream test is a qualitative immunoassay for the detection of human chorionic gonadotropin (hCG) in human urine for the early detection of pregnancy. hCG is a hormone produced by the placenta, which, in normal subjects, provides an early indication of pregnancy. The hCG Midstream test is an over-the-counter self test for the early detection of pregnancy. This test provides only a preliminary test result and positive test results should be evaluated with other data by a physician before diagnosing pregnancy.