Definition
The commercially available pregnancy test works by detecting the pregnancy hormone human chorionic gonadotropin (HCG) in a woman’s urine, which is only produced during pregnancy. Depending on the sensitivity of the test, the result is positive as early as eight days or only about two weeks after conception. These urine rapid tests/pregnancy tests are available in pharmacies and some drugstores.
They are offered particularly cheaply in Internet pharmacies. Furthermore, the doctor can quantitatively detect the hormone in the blood. This means that the progress of the pregnancy can also be assessed.
The urine test strip for a pregnancy test should be held in the morning urine if possible, as the HCG concentration is particularly high here. After contact with the urine, the result must usually be waited for a few minutes. During this time, if pregnancy occurs, any HCG present binds to a specific antibody and migrates with it as a complex to the test area of the strip.
Here another specific antibody is fixed, which in case of pregnancy stains the complex and thus creates a colored strip on the pregnancy test. Remains of the first, mobile antibody continue to move along the strip until they meet the control region. Here, an antibody is fixed against the antibody, which stains the antibody, thus creating another colored stripe.
While the first stripe is only visible in case of pregnancy, the second stripe must always be visible and thus functions as a check on the correct function of the test. Some patience is required for the application of the pregnancy test, as it can give information about a pregnancy after eight days at the earliest and even then still give false negative results. Furthermore, the pregnancy test can also give false positive results. This means that it indicates a pregnancy without the pregnancy actually being present. This can happen in the presence of special types of cancer (germ cell tumors), since these also produce the pregnancy hormone HCG.
