The principle is the same for everyone - they react only to the presence of a specific hormone in the urine, it cannot be otherwise, there is no other way. The main difference lies precisely on what day pregnancy should be determined, that is, the level of sensitivity to hCG.
The structure of express tests also differs. The simplest option and the most affordable on sale is a strip test. It is immersed in urine to the marked mark. Its main advantage is the price, since it is cheaper than the others. As for the disadvantages, this is a usage scheme that is quite complicated compared to the others. Well, it is not always convenient to empty into a jar, this is also a minus.
The strip is lowered into the urine to a certain level, where it must be kept for a strictly specified period of time - no less, but no more. Even a small mistake - and the result is already false.
The test cassette is considered more convenient. Sometimes such tests are also called tablet tests. In fact, this is the same strip test, but its convenient packaging eliminates the need to use a jar. It is enough to take a pipette and drip a few drops of urine into the window intended for it. Everything, you can wait for the result. And although the test strip is the same inside, it is this design that can significantly reduce the likelihood of obtaining a false result.
How the inkjet test works is clear from the name. He really is substituted under a stream of urine. Thus, the absence of the need for auxiliary devices is its main advantage. For ease of use, however, you will have to pay more.
But the highest level of comfort in the case when it is necessary to determine pregnancy will give an electronic test. The method of use is the same as that of the jet, that is, it is simply substituted under the stream of urine. But at the same time, there are no stripes - the test simply writes whether a woman is pregnant or not. There are models that can even show the approximate term of conception. In fact. this is a laboratory study at home, but it also costs accordingly.