Table of contents:
- Definition
- What is human chorionic gonadotropin (hcg)?
- When should I take human chorionic gonadotropin (HCG)?
- Precautions & warnings
- What should I know before taking human chorionic gonadotropin (hcg)?
- Process
- What should I do before taking human chorionic gonadotropin (HCG)?
- How is the human chorionic gonadotropin (HCG) process?
- What should I do after taking human chorionic gonadotropin (hcg)?
- Explanation of the Test Results
- What do my test results mean?
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Definition
What is human chorionic gonadotropin (hcg)?
A human chorionic gonadotropin (hCG) test is done to check for the hCG hormone in your blood or urine. Some hCG tests measure a definite amount and some just check to see if this hormone is present. hCG is made by the placenta during pregnancy. The hCG test can be used to detect pregnancy or as part of a pregnancy abnormality test.
hCG may also be produced abnormally if there are certain tumors, especially those that come from eggs or sperm (germ cell tumor). HCG levels are often tested in women who may experience abnormal growth of tissue in the uterus, molar pregnancy, or uterine cancer (choriocarcinoma) than in normal pregnancies. Some hCG tests may be done after a miscarriage to make sure a molar pregnancy doesn't occur. In a man, hCG levels may be measured to help see if he has testicular cancer.
hCG in pregnancy
The egg is normally fertilized by a sperm cell in the fallopian tube. Within 9 days after pregnancy, the egg moves from the fallopian tube to the uterus and attaches to the uterine wall. Once the egg attaches, the developing placenta begins to release hCG into the blood. Some of the hCG also passes into the urine. hCG can be found in the blood before the first missed menstrual period, approximately 6 days after implantation.
hCG helps maintain pregnancy and influences the development of the baby (fetus). Levels of hCG increase dramatically in the first 14 or 16 weeks after the last menstrual period (LMP), peak around 14 weeks following LMP, and then gradually decrease. The amount of hCG that increases early in pregnancy can provide information about pregnancy and the health of the baby. Immediately after delivery, hCG can no longer be found in the blood.
More hCG is released in multiple pregnancies, such as twins or triplets, than in singles. Less hCG is released when a fertilized egg attaches to a place other than the uterus, such as the fallopian tube. This is called an ectopic pregnancy.
When should I take human chorionic gonadotropin (HCG)?
The hCG test is done to:
- see if you are pregnant
- found an ectopic pregnancy
- find and check molar pregnancy treatment
- see if there is an increased chance of birth defects such as Down's syndrome. The test is used in combination with other tests
- find and examine cancer treatments that develop from eggs or sperm (germ cell cancer), such as ovarian or testicular cancer. In such cases, the alpha-fetoprotein test may be done in conjunction with the hCG test
Precautions & warnings
What should I know before taking human chorionic gonadotropin (hcg)?
The hCG blood test is generally more accurate than a urine test. If you are suspected of being pregnant even after the urine test results do not show pregnancy (negative result), a blood test can be done, or another urine test should be repeated within a week. The hCG result may remain high (positive) for up to 4 weeks after a miscarriage (spontaneous abortion) or therapeutic abortion.
A normal hCG value does not rule out a tumor in the uterus, ovaries, or testes. hCG is only one part of the overall assessment if a tumor is suspected. Blood levels of hCG are often used in maternal serum triple or quad tests.
Process
What should I do before taking human chorionic gonadotropin (HCG)?
If a blood sample is collected, you do not need to do anything prior to having this test. If a urine test is done, the first urine of the day is usually the best to use as it has the highest levels of hCG. A urine sample collected at least 4 hours after the last urination will also have high hCG levels.
How is the human chorionic gonadotropin (HCG) process?
hCG may be measured in a blood or urine sample.
Collection of blood samples
The doctor will clean a small area on the arm or elbow with an antiseptic cloth or alcohol pad. In some cases, the doctor will tie an elastic band around your upper arm to increase blood flow. This makes collecting blood from the arteries much easier.
Your arm will then be pierced with a needle that is inserted into the vein. A tube to collect blood is attached to the other end of the needle.
Once the blood is drawn, the doctor will take a needle and then use a cotton cloth and bandage to stop the bleeding from the needle pricked skin.
Collection of urine
If possible, collect a sample from the first urine of the day (this urine generally has the highest levels of hCG). A urine sample collected at least 4 hours after the last urination will also have the highest levels of hCG. Place a container in the urine stream, and collect approximately 4 Tbsp (60 ml) of urine.
Do not let the end of the container touch the genital area, and do not allow toilet paper, pubic hair, feces, blood or other foreign substances in the urine sample. Finish urinating into the toilet or urinal.
Place the lid on the container carefully, and return it to the laboratory. If you collect urine at home and can't return it to the lab in an hour, keep it in the refrigerator.
What should I do after taking human chorionic gonadotropin (hcg)?
You will be notified when you can get the test results. The doctor will explain the meaning of the test results. You must follow the doctor's instructions.
Explanation of the Test Results
What do my test results mean?
Normal
The normal scores listed on this list (called a 'reference range') are only a guide. This range varies from laboratory to laboratory, and your laboratory may have different normal scores. Your laboratory report will usually contain what ranges they are using. Your doctor will also check your test results based on your health condition and other factors. This means that if your test results fall into the abnormal range in this guide, it could be in your laboratory or for your condition the score falls into the normal range.
HCG levels in the blood
Men and women who are not pregnant: less than 5 international units per liter (IU / l).
Pregnant women, one week after pregnancy (about 3 weeks of last menstrual period): 5-50 IU / l.
Pregnant women, 2 weeks after pregnancy (about 4 weeks of last menstrual period): 50-500 IU / l.
Pregnant women, 3 weeks after pregnancy (about 5 weeks of last menstrual period): 100-10000 IU / l.
Pregnant women, 4 weeks after pregnancy (about 6 weeks of last menstrual period): 1080-30000 IU / l.
Pregnant women, 6-8 weeks after pregnancy (about 8-10 weeks of last menstrual period): 350-115000 IU / l.
Pregnant women, 12 weeks after pregnancy (about 14 weeks of last menstrual period): 12000-270000 IU / l.
Pregnant women, 13-16 weeks after pregnancy (about 15-18 weeks of last menstrual period): up to 200000 IU / l.
HCG levels in urine
Male: none (negative test)
Non-pregnant woman: none (negative test)
Pregnant woman: detectable (positive test)
High marks
If you are pregnant, very high levels of hCG could mean multiple pregnancies (such as twins or triplets), molar pregnancies, Down syndrome, or your pregnancy is older than expected.
In a nonpregnant man or woman, hCG levels mean that a tumor (cancerous or non-cancerous) that has developed from sperm or eggs (germ cell tumor), such as a testicular or ovarian tumor, is present. It may also mean certain types of cancer, such as cancer of the stomach, pancreas, colon, liver, or lung.
Low marks
If you are pregnant, a low hCG level could mean an ectopic pregnancy, infant mortality, or that your pregnancy was later than expected.
If you are pregnant, an abnormally reduced level of hCG can mean that you are more likely to have a miscarriage (spontaneous abortion).