The cost of the blood HCG test is around$90. The blood HCG test is mainly used for early pregnancy screening. In normal pregnancy, when the fertilized egg is laid, i.e. on the 6th day after ovulation, the trophoblast layer of the fertilized egg forms and starts to produce HCG, which can be measured in the peripheral blood about 1 day later and doubles every 1.7-2 days thereafter, reaching about 100 U/L on the 14th day after ovulation is measured, peaking at about 50,000-100,000 U/L on the 8th-10th week of pregnancy and declining rapidly thereafter. In mid to late pregnancy HCG is only 10% of its peak. Since HCG is also seen in trophoblastic diseases, germ cell tumors and other malignant tumors, such as lung, kidney and liver tumors that also produce HCG, it is important to suspect the presence of trophoblastic diseases if there is an abnormal increase in HCG during early pregnancy.