HCG (human chorionic gonadotropin) pregnancy test products are tools used to detect whether a woman is pregnant or not.

I. Product Types

1. Pregnancy Test Sticks
   This is the most common type of HCG pregnancy test product. It is usually a small plastic stick with an absorbent window at one end for absorbing urine samples. It contains chemical reagents inside. When HCG in the urine reacts with the reagents, corresponding results will appear in the display window. For example, the appearance of two red lines usually indicates pregnancy, while one red line indicates no pregnancy. This product is easy to operate, and women can conduct the test privately at home without the assistance of professionals.
2. Pregnancy Test Papers
   The principle of pregnancy test papers is similar to that of pregnancy test sticks, but they are usually in the form of paper strips. When using them, one end of the test paper needs to be dipped into the urine sample so that the test paper can fully absorb the urine. Then, the pregnancy status is judged according to the color change in the display area of the test paper. Some pregnancy test papers may have a control area and a test area. When a specific color change (such as darkening) appears in the test area and the control area develops color normally, it indicates pregnancy. This product is relatively inexpensive and convenient for purchasing in large quantities for multiple tests.
3. Electronic Pregnancy Test Products
   This is a relatively advanced pregnancy test product. It generally consists of a test stick and an electronic display screen. The test stick is used to collect urine samples, and the internal sensors will detect the HCG level in the urine. Then, the test results will be displayed on the electronic display screen in the form of numbers or symbols. For example, it may display text information such as “pregnant” or “not pregnant”, or use “+” to indicate pregnancy and “-” to indicate no pregnancy. This product has relatively high accuracy and the display of results is more intuitive.

II. Detection Principle

HCG pregnancy test products are mainly based on the principle of antigen-antibody reaction. They contain specific antibodies against HCG. When HCG in urine samples binds to these antibodies, a series of chemical changes will be triggered, resulting in observable signals. In pregnancy test sticks and pregnancy test papers, this signal is usually a color change; in electronic pregnancy test products, the chemical signal is converted into an electronic signal by electronic sensors and then displayed.

III. Usage Methods

1. Usage of Pregnancy Test Sticks and Pregnancy Test Papers
   For pregnancy test sticks, first, make sure to choose the appropriate time for use. Generally, it is recommended to conduct the test about one week after the menstrual period is delayed. When using it, align the absorbent window with the urine stream or dip the pregnancy test stick into the urine sample (be careful not to exceed the specified mark line), keep it for a few seconds, then take it out and place it flat on a clean surface to wait for the results. For pregnancy test papers, dip one end of the test paper into the urine according as required by the instructions. The soaking time should be strictly in accordance with the instructions, usually ranging from a few seconds to dozens of seconds. Then take out the test paper, wait for the color change and read the results.
2. Usage of Electronic Pregnancy Test Products
   First, turn on the power of the electronic pregnancy test product. Then put the test stick into the urine in the correct way to collect the sample. Wait for a period of time (usually the product manual will specify the specific waiting time, generally a few minutes), and the electronic display screen will show the test results.

IV. Application Scenarios

1. Home Self-testing
   HCG pregnancy test products are mainly used for women to self-test whether they are pregnant at home. It is very convenient for those women who want to know whether they are pregnant as early as possible. For example, if a couple is planning to have a child, the woman can conduct the test in time after the menstrual period is delayed, so that she can detect the pregnancy at an early stage and arrange subsequent prenatal examinations and other matters.
2. Auxiliary Detection in Medical Institutions
   In hospitals and clinics, these products can also be used as a preliminary detection means. Before patients undergo more complex pregnancy tests (such as blood tests, ultrasound examinations), doctors can first ask patients to use HCG pregnancy test products for a quick test to obtain a preliminary result, which helps doctors judge whether further in-depth examinations are needed.