β-HCG is the beta subunit of human chorionic gonadotropin, a glycoprotein secreted by placental trophoblast cells. β-HCG is an important indicator for detecting early pregnancy, in addition to diagnosing trophoblastic disease.1. Early pregnancy: β-HCG concentration is significantly elevated under physiological conditions and can be used to diagnose early pregnancy. In normal individuals, β-HCG is <5 IU/L. If it is greater than 5 IU/L, pregnancy is suspected, and if it is greater than 10 IU/L, pregnancy can be basically diagnosed. In addition, the value of β-HCG can reflect the development of fetus, if it increases more than 66% every 2 days, it is a good doubling, usually intrauterine pregnancy, less than 66% is usually ectopic pregnancy or pre-eclampsia; 2. Trophoblastic disease: according to the concentration of β-HCG can assist in the diagnosis of trophoblastic tumor, usually in the case of excluding early pregnancy, β-HCG concentration >10IU/L, even more than 20IU/L, the presence of trophoblastic tumors, such as chylothorax, choriocarcinoma, etc., is highly suspected, and it also has certain auxiliary diagnostic and monitoring effects on breast cancer, testicular cancer, ovarian cancer, etc. However, relying on β-HCG concentration alone cannot make a definite diagnosis, and it needs to be combined with ultrasound, pathological examination and other means to confirm the diagnosis. When performing the beta-HCG test, a blood specimen should be collected. The day before the blood draw, you should not eat too greasy or high-protein food and avoid drinking alcohol, as the alcohol content in the blood can affect the test results.