What is Human Chorionic Gonadotropin (hCG) Blood Test?
The human chorionic gonadotropin (hCG) blood test measures the level of hCG hormone present in a sample of your blood.
hCG is produced during pregnancy. Your doctor may refer to the hCG blood test by another name, such as the:
- Beta-hCG blood test
- quantitative blood pregnancy test
- quantitative hCG blood test
- quantitative serial beta-hCG test
- repeat quantitative beta-hCG test
There are important differences between hCG blood tests and the hCG urine tests that you can purchase over the counter.
Urine tests can be influenced by factors such as dehydration and the time of day that you test, while an hCG blood test can provide conclusive results even in cases where hCG levels are quite low.
Why is Human Chorionic Gonadotropin (hCG) Blood Test performed?
The hCG blood test is performed to:
- Confirm pregnancy
- Determine the approximate age of the fetus
- Diagnose an abnormal pregnancy, such as an ectopic pregnancy
- Diagnose a potential miscarriage
- Screen for down syndrome
The hCG blood test is sometimes used to screen for pregnancy before you undergo certain medical treatments that could potentially harm a developing baby. Examples of these treatments include X-rays.
If an hCG test concludes that someone is pregnant, healthcare professionals can ensure that they’re protected and that the fetus isn’t harmed by those medical treatments.
Beta hCG is considered a tumor marker, which means it’s a substance that’s excreted by some kinds of tumors. That’s why, in some cases, the hCG blood test may also be used to evaluate and manage certain types of cancer.
What should I know before receiving Human Chorionic Gonadotropin (hCG) Blood Test?
No test is 100 percent accurate every time. The hCG test can give both false-negative results and false-positive results for pregnancy. Your doctor will help you figure out your results or perform follow-up testing if there’s any doubt.
Certain medications, including those that contain hCG, can interfere with hCG blood test results. These include fertility drugs such as Profasi, Pregnyl, and Pergonal.
Smoking marijuana can also result in elevated hCG levels.
Test results can also be influenced by the presence of germ cell tumors. Germ cell tumors can be cancerous or benign, and they’re usually found in the reproductive organs. These tumors grow in the same cells as your eggs or sperm.
A high hCG level in absence of pregnancy could indicate that your doctor needs to do more testing to see if cancer is a factor.
If an hCG test comes back negative, that generally means you’re not pregnant.
However, if the test was performed too early in the pregnancy, before your body has had time to produce enough hCG, you can get a false negative.
If there’s a false-negative test result, the test indicates that a woman isn’t pregnant, when in fact she is.
Because hCG levels change so quickly during early pregnancy, the hCG blood test should be repeated within 48 to 72 hours to observe how the hormone level is changing.
On the other hand, hCG can be present in some nonpregnant conditions, potentially causing a false-positive hCG pregnancy test.
If there’s a false-positive test result, the test indicates that a woman is pregnant, when in fact she isn’t.
It’s also possible to get a false-positive result if your body produces certain types of antibodies that have fragments of the hCG molecule, or if there were errors in the lab.
If there’s any doubt about the results, a different testing method can be used to confirm.
How to prepare for Human Chorionic Gonadotropin (hCG) Blood Test?
No particular preparation is required for the hCG blood test.
What happens during Human Chorionic Gonadotropin (hCG) Blood Test?
A healthcare professional takes a blood sample by following these steps:
- An elastic band is wrapped around your upper arm to stop the blood flow and to make the veins in your arm more visible. This is so the needle can be inserted easier.
- A vein is located and the skin around the vein is cleaned with alcohol.
- The needle is inserted into the vein and a tube is attached to the end of the needle to collect the blood.
- After enough blood is collected, the elastic band is removed from your arm.
- As the needle is removed, cotton or gauze is placed onto the puncture site.
- Pressure is applied to the cotton or gauze, and it’s secured with a bandage.
What happens after Human Chorionic Gonadotropin (hCG) Blood Test?
Your blood will be sent to a lab for testing. This test doesn’t require any special aftercare. You may resume your daily activities unless instructed otherwise by your doctor.
If you have any questions about the Human Chorionic Gonadotropin (hCG) Blood Test, please consult with your doctor to better understand your instructions.
Explanation of results
What do my results mean?
When your lab test comes back, your doctor will tell you what your hCG levels are. These levels are measured in milli-international units of hCG hormone per milliliter of blood (mIU/mL).
- An hCG level of less than 5 mIU/mL is considered negative for pregnancy, and anything above 25 mIU/mL is considered positive for pregnancy.
- An hCG level between 6 and 24 mIU/mL is considered a grey area, and you’ll likely need to be retested to see if your levels rise to confirm a pregnancy.
A low hCG level can mean any number of things and should be rechecked within 48-72 hours to see how the level is changing.
A low hCG level can indicate:
- Miscalculation of pregnancy dating
- Possible miscarriage or blighted ovum
- Ectopic pregnancy
A high level of hCG can also mean a number of things and should be rechecked within 48-72 hours to evaluate changes in the level.
A high hCG level can indicate:
- Miscalculation of pregnancy dating
- Molar pregnancy
- Multiple pregnancy
Depending on the laboratory and hospital, the normal range for Human Chorionic Gonadotropin (hCG) Blood Test may vary. Please discuss with your doctor any questions you may have about your test results.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Human Chorionic Gonadotropin (hCG) Blood Test. https://www.healthline.com/health/hcg-blood-test-quantitative. Accessed October 25, 2018.
Human Chorionic Gonadotropin (HCG): The Pregnancy Hormone. http://americanpregnancy.org/while-pregnant/hcg-levels/. Accessed October 25, 2018.
Review Date: November 5, 2018 | Last Modified: November 5, 2018