Beta-chorionic gonadotropin in the blood

Reference values (norm) of concentration of beta-chorionic gonadotropin in blood serum: adults - up to 5 U / ml; at a pregnancy of 7-10 days - more than 15 IU / ml, 30 days - 100-5000 IU / ml, 10 weeks - 50 000-140 000 IU / ml, 16 weeks - 10 000-50 000 IU / ml. The half-life is an average of 2.8 days.

Chorionic gonadotropin - a hormone consisting of 2 subunits - alpha and beta, non-covalently connected to each other; the alpha subunit is identical to the alpha subunit of LH, FSH and TSH, the beta subunit is specific for chorionic gonadotropin.

Beta-chorionic gonadotropin is a glycoprotein secreted by the syncytial layer of trophoblast during pregnancy. It supports the activity and existence of the yellow body, stimulates the development of the embryoblast. Excreted in the urine. Detection of beta-chorionic gonadotropin in serum serves as a method for early diagnosis of pregnancy and the pathology of its development. In oncology, the definition of beta-chorionic gonadotropin is used to control the treatment of trophoblastic and germinogenic tumors. The half-life of beta-chorionic gonadotropin is 3 days. In men and non-pregnant women, a pathological increase in the concentration of beta-chorionic gonadotropin is a sign of the presence of a malignant tumor.

Diseases and conditions in which the concentration of beta-chorionic gonadotropin in the blood changes

Increase in concentration

• Pregnancy
• Germinogenic tumors (chorionepithelioma)
• Bumpy drift
• Malformations of the neural tube of the fetus, Down's syndrome
• With incomplete removal of the fetal egg during the abortion
• Trophoblastic tumor
• Teratoma of the testicle
• Multiple pregnancy
• Menopause
• Endocrine disorders
• Seminom

Reduction in concentration

• Decrease in concentration relative to the phase of pregnancy indicates the presence of:
  • ectopic pregnancy;
  • damage to the placenta during
  • pregnancy;
  • threat of miscarriage

The sensitivity of the determination of β-CG in the blood in carcinoma of the ovary and placenta is 100%, in chorionadenoma 97%, in non-seminominous germinomas 48-86%, in seminoma 7-14%. Elevated concentrations of β-chorionic gonadotropin were observed in 100% of patients with trophoblast tumors and in 70% of patients with non-seminiferous testicular tumors containing syncytiotrophoblast elements.

Germins of the testicles are one of the most frequent oncological diseases of young men (20-34 years). Due to the fact that the histological type of tumor can change during therapy, it is recommended to carry out a combined determination of β-CG and AFP in germinomas. Seminomas, disgerminomas and differentiated teratomas are always AFP-negative, yolk sac tumors in their pure form are always AFP-positive, while carcinomas or combined tumors, depending on the mass of endodermal structures, can be either AFP-positive or AFP-negative. Thus, for germin, β-CG is a more important marker than AFP. The joint determination of AFP and β-CG is particularly indicated during treatment with germin. Profiles of these two markers may not coincide. The concentration of AFP is reduced to normal values within 5 days after radical surgery, reflecting a decrease in the total mass of the tumor. After chemotherapy or radiotherapy, on the contrary, the concentration of AFP will reflect only a decrease in the number of AFP-producing cells, and since the cellular composition is germin mixed, the determination of β-CG is necessary to evaluate the effectiveness of therapy.

The combined determination of AFP and β-CG allows a sensitivity of 86% to be achieved in the diagnosis of recurrence of non-seminomatous testicular tumors. The increasing concentration of AFP and / or β-CG indicates (often several months earlier than other diagnostic methods) the progression of the tumor and, consequently, the need for treatment change. Initially, high values of AFP and β-CG in the blood indicate a poor prognosis.

[1], [2], [3], [4], [5]