First Response Pregnancy Test Commercial 1989

Identified in the early 20th century, human chorionic gonadotropin (hCG) is a glycoprotein hormone that rises quickly in the first few weeks of pregnancy, typically reaching a peak at 8- to 10-weeks gestational age.[4][5] hCG is produced by what will become the placenta.[6] hCG testing can be performed with a blood (serum) sample (typically done in a medical facility) or with urine (which can be performed in a medical facility or at home). The assays used to detect the presence of hCG in blood or urine are generally reliable and inexpensive. Secretion of hCG can occur as soon as 6 days following ovulation and on average 8-10 days following ovulation; this is the earliest hCG can be detected in a blood sample. The hCG concentration in blood is higher than in urine. Therefore, a blood test can be positive while the urine test is still negative.

Qualitative tests (yes/no or positive/negative results) look for the presence of the beta subunit of human chorionic gonadotropin (hCG) in blood or urine. For a qualitative test the thresholds for a positive test are generally determined by an hCG cut-off where at least 95% of pregnant women would get a positive result on the day of their first missed period.] Qualitative urine pregnancy tests vary in sensitivity. High-sensitivity tests are more common and typically detect hCG levels between 20-50 milli-international units/mL (mIU/mL). Low-sensitivity tests detect hCG levels between 1500-2000 mIU/mL and have unique clinical applications, including confirmation of medication abortion success. Qualitative urine tests available for home use are typically designed as lateral flow tests.