A pregnancy test determines whether human chorionic gonadotropin (hCG) is present in a woman’s urine, a specific hormone that is produced by the chorionic villi after embryo implantation.
The analyzers are designed in such a way that if hCG molecules are present, the chemical reagent reacts with them and colors the second strip blue or red. The more hormone in the urine, the brighter the result.
HCG reaches high values 10–14 days after implantation. Manufacturers recommend performing the test on the 2-3rd day of the delay in order to get a clear positive result in the form of two bright stripes. One clear strip indicates a negative result, which means the absence of hCG and pregnancy, respectively.
A weak, barely visible, but still visible second line on the test is a dubious result. The hCG level does not reach the concentration during a normally developing pregnancy and requires repeated analysis and consultation with a specialist.