The difference between blood hcg and urine hcg

Everyone should go to the hospital for regular physical examinations, because physical examinations are the best way to quickly detect the presence of physical diseases and prevent some physical diseases. During a physical examination, there are some indicators that are difficult to understand. For example, hcg is an item that is often examined during physical examinations. In fact, hcg is mainly an important indicator to reflect whether a woman is pregnant, but what is the difference between checking blood hcg and hcg during the examination?

What is the difference between blood hCG and urine hCG?

hCG stands for human chorionic gonadotropin, which is composed of α and β dimers of glycoprotein. After a woman becomes pregnant, the hCG originally present in her blood and urine will fluctuate as the gestational age increases. Therefore, whether a woman is pregnant can be determined based on the changes in hCG.

The human chorionic gonadotropin (hCG) test is currently the most advanced pregnancy test. Common test methods include blood hCG test and urine hCG test. This test determines whether a woman is pregnant by checking the presence of β-subunits in the blood and urine. So, what is the difference between blood hCG and urine hCG? Generally speaking, urine hCG is not as sensitive as blood hCG in determining pregnancy. The reference values ​​of blood hCG and urine hCG are also different:

Urine hCG (hCG semi-quantitative method): non-pregnant women <25IU/L, 40 days of pregnancy >5000IU/L, 60-70 days of pregnancy >(8-32)×104IU/L (urine hCG level is highest in the early morning, close to serum level).

Blood hCG levels during normal pregnancy:

Gestational weeks hCG (IU/L)

0.2-1 week 5-50

1-2 weeks 50-500

2-3 weeks 100-5000

3-4 weeks 500-10000

4-5 weeks 1000-50000

5-6 weeks 10,000-100,000

6-8 weeks 15,000-200,000

February-March 10,000-100,000

The examination of hCG is of great significance for the diagnosis of early pregnancy, and has certain value in the diagnosis, differentiation and course observation of pregnancy-related diseases, trophoblastic tumors and other diseases.

When should blood hCG be tested?

Blood hCG test can be used to determine early pregnancy and diagnose related diseases. Therefore, the purpose is different and the time of the test is also different:

1. Confirm pregnancy - the earliest can be 8-10 days after intercourse

The best time to test hCG blood is 8-10 days after intercourse. At this time, the test can be used as a pregnancy test to confirm pregnancy. At the same time, in the first 3 months of pregnancy, this test can also be used to diagnose single or multiple pregnancies.

2. Diagnosis of abnormal pregnancy - test whether the hCG content doubles every 2 days

After a woman becomes pregnant, an increase in the β-hCG value in the blood can be detected from the 9th to 11th day, and the β-hCG value can double every two days thereafter. If the test shows a slow increase for two consecutive times, it may be caused by factors such as ectopic pregnancy, abnormal embryo or intrauterine growth retardation.

If the abnormal pregnancy is a hydatidiform mole, the hCG concentration in the serum will be much higher than the value in the corresponding month of a normal pregnancy. Therefore, this difference can be used as an auxiliary diagnosis of hydatidiform mole, which is usually performed in the first 3 months of pregnancy.

3. Down syndrome screening - 15-20 weeks of pregnancy

Down syndrome screening detects the levels of AFP and β-hCG in venous blood and comprehensively calculates the risk of the fetus having Down syndrome. The best time to do this test is between 15 and 20 weeks of pregnancy.

4. Judgment of miscarriage: 4 days after delivery or 13 days after artificial abortion.