The HCG pregnancy test is a method to determine whether a woman is pregnant by detecting the level of human chorionic gonadotropin (HCG) in human blood or urine. It has several specific applications in clinical practice and daily life:

Self-testing at Home: After a woman’s menstrual period is delayed, she can use an early pregnancy test strip to conduct a urine HCG test. Drop the urine onto the test strip. If two red lines appear, it generally indicates pregnancy. This method is simple to operate and has a low cost, allowing women to preliminarily understand their pregnancy status.
Clinical Diagnosis in Hospitals: For women with suspected pregnancy symptoms or abnormal menstrual cycles, doctors usually recommend an HCG pregnancy test first. By detecting the level of HCG in blood or urine and combining it with the time of the last menstrual period and clinical symptoms, doctors can accurately determine whether a woman is pregnant. Blood HCG testing is more accurate and can detect extremely low levels of HCG, enabling the detection of pregnancy in the early stage.

Auxiliary Judgment: During a normal pregnancy, the HCG level rises rapidly in the early stage of pregnancy, approximately doubling every 48 hours. However, in the case of ectopic pregnancy (tubal pregnancy), since the fertilized egg implants in a site outside the uterus and the trophoblast cells develop poorly, the HCG level rises slowly. Continuously monitoring the blood HCG level and, if its growth rate does not conform to the normal pregnancy pattern, combined with ultrasound examination, can help doctors determine whether it is an ectopic pregnancy so that timely treatment measures can be taken to avoid serious consequences.
Treatment Monitoring: For patients diagnosed with ectopic pregnancy who choose conservative treatment, it is necessary to regularly detect the HCG level to evaluate the treatment effect. If the HCG level gradually decreases, it indicates that the treatment is effective and the ectopic pregnancy lesion is being absorbed. If the HCG level does not decrease but instead increases or remains at a high level, it may suggest that the treatment has failed, and other treatment methods such as surgery should be considered.

Monitoring of Miscarriage: When vaginal bleeding, abdominal pain, and other miscarriage symptoms occur in the early stage of pregnancy, detecting the HCG level can help determine the type and prognosis of miscarriage. If the HCG level continues to decline and no embryonic development or fetal heartbeats are seen in the ultrasound examination, it may indicate inevitable miscarriage or missed miscarriage, and timely curettage and other treatments are required. If the HCG level decreases but still shows an upward trend and the embryo is found to be alive in the ultrasound examination, it may be a threatened miscarriage, and miscarriage prevention treatment can be carried out while continuing to monitor changes in HCG and ultrasound.
Diagnosis and Monitoring of Trophoblastic Diseases: In trophoblastic diseases such as hydatidiform mole and choriocarcinoma, the HCG level will be abnormally elevated, much higher than that in a normal pregnancy. By detecting the HCG level and combining it with clinical symptoms and ultrasound examination, doctors can diagnose trophoblastic diseases. During the treatment process, continuous monitoring of the HCG level can evaluate the treatment effect and determine whether the disease recurs.

Judgment of Embryo Implantation: In assisted reproductive technologies such as in vitro fertilization, after embryo transfer, detecting the blood HCG level can determine whether the embryo has implanted successfully. Generally, the first HCG test is carried out 10 to 14 days after the transfer. If the HCG level increases, it indicates that the embryo has implanted, and subsequent pregnancy monitoring and miscarriage prevention treatment can be continued.
Assessment of Pregnancy Health: During pregnancy after successful assisted reproduction, regular detection of the HCG level is also important. It can help doctors understand the development of the embryo or fetus, timely detect possible problems such as early miscarriage and ectopic pregnancy, and provide a basis for pregnancy management.