Rapid test kit detects pregnancy by determining the presence of human chorionic gonadotropin (hCG): It's referred to as a "combo" test because either serum or urine can be used in test.. CLIA waived for urine testing; CLIA moderately complex for serum testing. Sensitive to 20mIU/mL of hCG. Cassette test with pipette prepackaged in foil pouch.