The fertilization of the woman’s egg by the man’s sperm takes place in the woman’s tubes, and as a result of fertilization, an embryo is formed. In the outer layer of the embryo, cells called trophoblastic cells develop, which enable the embryo to attach to the uterine wall. These trophoblastic cells secrete the HCG hormone called Human Chorionic Gonadotropin hormone. Within 5 to 6 days after fertilization, the embryo settles in the inner layer of the uterus and continues to secrete more and more HCG hormone. Women cannot understand this process because the expected menstrual date has not come yet. Secreted HCG is found in blood and urine, but measurements made before the menstrual day cannot show whether pregnancy is present or not.
If the menstrual period does not occur, the HCG hormone can be measured in the blood or urine to determine whether there is a pregnancy or not. Tests performed before the expected period do not give accurate information, the HCG test has nothing to do with ovulation tests, ovulation tests can only give information about the day of ovulation and do not show whether there is pregnancy or not.
What is the HCG Test and How Is It Done?
Women who are suspected of pregnancy can tell if they are pregnant with an HCG test from blood or urine. These tests are easily done at home and health centers today. It is detected earlier in blood than in urine. The test made from the blood sample taken from the arm can clearly measure the amount of the hormone and determine the actual level of HCG, while giving information about the approximate week of pregnancy, while the HCG test in the urine can only give information as if there is a pregnancy or not. The most suitable sample for a urine test is the first urine in the morning.
Can the HCG Test Be Used in the Diagnosis of Other Diseases Apart from Pregnancy?
The hCG test is usually included in the measurements of the double and triple screening tests used for Down Syndrome screening during pregnancy, as well as determining whether the woman is pregnant. Produced in some types of cancer, such as ovarian cancer, this hormone is used to determine whether men have testicular cancers. HCG may also be elevated in cancers of the stomach, pancreas, large intestine, lung or liver. It is used in the follow-up of the diagnosis and treatment of hydatiform mole, which is called grape pregnancy in women. If pregnancy is suspected before medical interventions, a HCG test should be performed.
HCG values in the blood are lower than expected in cases of ectopic pregnancy, death of the baby in the womb, a pregnancy with a shorter duration than the last menstrual period or miscarriage.
How Are HCG Test Normal Values Evaluated?
It may differ depending on the laboratory where the HCG test is performed, the method used, or the instruments in which HCG is measured. Values below 5 U/L in men and below 50 U/L in women are considered negative. However, if the HCG value is below 50 U/L in women with suspected pregnancy, it can be re-measured every 48 hours to see if the HCG level has increased.
Issues to Consider Before Giving a Test
Use of heparin, hypnotic, antipsychotic and anti-nausea drugs, some diuretics, or HCG injection for infertility treatment, false positive values may occur in cases of a recent miscarriage. Patients using drugs that affect the test results should definitely inform the doctor requesting the test about their condition. Drinking too much water before the urine test will dilute the urine, which can lead to false negative results.
Tests performed earlier than the calculated date or incorrect calculation of the last menstrual period may result in low or negative tests. For this reason, in doubtful cases, the test should be repeated after a few days.
HCG values are not a simple blood test, besides whether the pregnancy is healthy, it also includes many clinical conditions about other diseases other than pregnancy. Your hCG test result should be evaluated together with your doctor’s examination. Although there are possible findings of pregnancy and HCG values show pregnancy, the definitive diagnosis of a healthy pregnancy is made by seeing the gestational sac and the baby as a result of the ultrasound examination.