From Cereal Grains to Immunochemistry—What Role Have Antibodies Played in the History of the Home Pregnancy Test

Abstract

Today, the home pregnancy test is the most frequently performed laboratory test for self-diagnosis (home diagnostic test). It is also the first laboratory test that has been adapted for self-use at home. This is probably because women have always wanted to know the answer to the question: “Am I pregnant or not?” and always preferred to know the answer to this question intimately and in a discreet way. The history of the pregnancy test is also an interesting example of how the discovery of antibodies and the development of in vitro diagnostic methods based on the antigen–antibody reaction were important for the development of laboratory and clinical diagnostics. Immunodiagnostic techniques (based on the antigen–antibody reaction) are currently the basis of modern specialist laboratory diagnostics, which is essential in clinical diagnosis. The history of the pregnancy test is an interesting one and dates back to ancient times. A pregnancy test is defined as a procedure intended to reveal the presence or absence of pregnancy. Nowadays, every pregnancy test is based on the detection of human chorionic gonadotropin (hCG) in urine or blood. Human chorionic gonadotropin is secreted by the placenta right after a fertilized egg cell implants in the uterus and can be detected in both the urine and blood of pregnant women. Urine pregnancy tests are convenient for self-use at home. Blood tests are performed in medical laboratories. Specialized laboratory methods not only detect hCG but also determine the concentration of this hormone. However, both of these methods are highly accurate and common. Throughout the ages, many different methods were used to detect pregnancy at the earliest stage. Grain, wine, and various small animals were used as research tools. These were both long-term and often unreliable; most were based on folk beliefs and superstitions. Animal pregnancy tests were the first biological tests used in this field. This was a significant advance in the accurate detection of relatively early pregnancy. Animal tests in modern times are considered cruel and inhumane, no matter how reliable their results can be. Their place is now taken by much more specific, more sensitive, and definitely more ethical immunochemical tests. The pregnancy test and the methods to find out whether a woman is pregnant have gone through massive transformations, from bioassays using plants to bioassays on animals to advanced immunochemical techniques and biosensors. Modern pregnancy tests are not invasive and are very sensitive. Nowadays, it takes only about 3 min to know the answer to the question: “Am I pregnant or not?”. However, it was not always as simple as it is today. This manuscript aims to show the important role played by antibodies in the development of laboratory and clinical diagnostics in the example of the interesting history of the pregnancy test.