HCG Beta Total, (BHCG)

Description

What is BHCG?

Beta Human Chorionic Gonadotropin (β-hCG ) Total test measures the amount of human chorionic gonadotropin (hCG) hormone in the blood preferably 10 days post conception. The levels of this hormone increase in the blood during early pregnancy, between 8 to 10 weeks, after which they start falling.

This test is commonly used to confirm pregnancy. However, it can also help to diagnose suspected tumors, post-miscarriage monitoring and detect ectopic pregnancy. After 6-7 weeks of pregnancy, hCG levels are not very helpful to test for the viability of the pregnancy. Instead, an ultrasound is done to confirm the presence of a fetal heartbeat. Low β hCG is seen in miscarriage and ectopic pregnancy while high β-hCG is observed in case of multiple pregnancies.

Why is BHCG done?

• To confirm pregnancy
• To diagnose pregnancy in the location other than the normal (Ectopic pregnancy)
• For first trimester screening of genetic diseases like Down’s syndrome and Trisomy 18
• To diagnose the presence of Gestational Trophoblastic Disease (GTD)
• To diagnose any suspected tumors like Teratomas, Testicular tumors, Ovarian germ cell tumors

What does BHCG Measure?

b-hCG test measures the levels of b-hCG in blood. b-hCG is a hormone which is normally produced by the cells in the developing placenta, during pregnancy. b-hCG levels increase during the initial period of the pregnancy. The role of b-hCG in early pregnancy is to maintain the corpus luteum (the hormone-secreting structure that develops in an ovary). During the first three weeks, production of b-hCG increases reaching to peak levels at 10th week (from the last menstrual cycle). After that, the levels of b-hCG start falling to negligible levels within a few weeks after delivery.

In men and women, b-hCG is normally found in small amounts. b-hCG is composed of two big molecules known as alpha and beta subunit. The structure of the alpha subunit is similar to the structure of Follicle-stimulating hormone and Luteinizing hormone. The beta subunit is different and is found only in b-hCG. That is why b-hCG test is done to decrease the risk of cross-reaction.

Interpreting BHCG results

Interpretations

Low b-hCG levels are seen in the following conditions:

• Error in calculation of pregnancy date
• Miscarriage
• The blighted ovum (Pregnancy without embryo)
• Ectopic pregnancy (Pregnancy other than normal location or outside of the uterus)

High b-hCG levels are seen in the following conditions:

• Error in calculation of pregnancy date
• Molar pregnancy (an abnormal pregnancy where the baby does not develop)
• More than one pregnancy (Twins or Triplets)