The principle of a pregnancy test
A pregnancy test allows a reasonably high degree of reliability to diagnose its occurrence or absence. Its use is very convenient, because a woman can perform a simple analysis at home.
Most manufacturers of the tests say that the accuracy of the results of the rapid analyses performed with the use of their products, is 95-98%. Currently, there are several varieties of test strips. The most expensive but the most accurate are jet tests.
The principle of operation of all products of pregnancy are the same. Manufacturers impregnated strips of special reagents that can react with human chorionic gonadotropin. The level of HCG in the urine begins to grow immediately after attachment of the embryo to the uterine wall. Every few days the concentration of the hormone in biological fluids is increased about 2 times.
In order for the reaction, it is necessary to lower the test strip into the container of urine to the specified level. The time of incubation, as a rule, is 20-30 seconds. More detailed recommendations can be found in the instructions written by the manufacturer. It is usually found in the packaging with the test.
What happens if you overdo the pregnancy test in the urine
Incorrect application of the test may result in false result. For example, if you hold it in a container of urine for more than 20 seconds, the stripes can not be manifested. This is because prolonged exposure of the biological fluid to the reagent of their partial or complete washout. After washing out of special substances test is not suitable for use, as it already will be missing reagents that can react with human chorionic gonadotropin.
Experts claim that in excess of time of exposure of the test strip in the urine may also receive a false positive result. Some expensive tools for a rapid analysis of pregnancy, made so qualitatively that the destruction of the reagents is impossible, even with prolonged contact with urine.
When increasing the exposure time of a quality test strip in a biological fluid the amount of hormone that reacts with the reagents increases. This means that the second strip can be painted in pink color, even in the absence of pregnancy.