What is the hCG quantitative blood test?
human chorionic gonadotropin (hCG) blood test measures the level of
hCG hormone present in a sample of your blood. HCG is a hormone that is
produced during pregnancy. Your doctor may refer to the hCG quantitative test by
another name, including:
- quantitative serial beta-hCG test
- repeat quantitative beta-hCG test
- beta-hCG blood test
- quantitative blood pregnancy test
In some cases, the hCG quantitative blood test may also be used
to evaluate and manage certain types of cancer.
What is human chorionic gonadotropin (hCG)?
During pregnancy, cells in the developing placenta make human chorionic gonadotropin, or hCG.
The placenta is the sac that nourishes the egg after it’s fertilized and
attaches to the uterine wall.
HCG can first be detected in a blood sample about 11 days after
conception. Levels of hCG continue to double every 48 to 72 hours. They reach their
peak around eight to 11 weeks after conception. HCG levels then decline and level
off, remaining steady for the rest of your pregnancy.
Why is the hCG quantitative test performed?
The hCG quantitative test is performed to:
- confirm pregnancy
- determine the approximate age of the fetus
- diagnose an abnormal pregnancy, such as an ectopic
- diagnose a potential miscarriage
- screen for Down’s syndrome
In some instances, the hCG blood test is used to screen for
pregnancy before a woman undergoes certain medical treatments that could potentially
harm a developing baby, such as X-rays, to make completely
sure the woman is not pregnant. This ensures that the woman is protected and that the fetus
isn’t harmed by the procedure.
How is the hCG quantitative test performed?
The hCG quantitative test measures the level of hCG hormone in a
blood sample. A healthcare professional takes a blood sample by following these
- An elastic band is wrapped around your upper arm
to stop the blood flow and to make the veins in your arm more visible 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.
While the needle is being inserted, you may feel a brief stinging
or pinching sensation, or you may not feel anything at all. When the needle is
in the vein, you may feel minor discomfort or stinging. Afterward, you may feel
some mild throbbing at the puncture site.
After your hCG levels have been measured in the blood sample, the
results are sent to your doctor who may request an appointment with you to
discuss the results of the test.
There are no particular preparations required for the hCG quantitative
What risks are associated with the hCG quantitative test?
Risks involved with having blood taken are minimal. There may be
a small amount of bruising where the needle was inserted, which can be
minimized by applying pressure to the area for several minutes after the needle
In very rare cases, the following may occur:
- excessive bleeding
- hematoma, which happens when blood accumulates
under your skin
- infection at the needle site
Understanding hCG quantitative test results
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).
This table shows the normal hCG levels during pregnancy for each
week from your last menstrual period, according to the American
Normal hCG levels in non-pregnant women are less than 5.0 mIU/ml,
and in postmenopausal women normal levels are anything less than 9.5 mIU/ml.
If your hCG levels are outside of the normal range, it could mean
a variety of things. Your doctor will help you interpret the results.
Levels of hCG that are lower than normal could mean:
- a miscalculation of pregnancy dating
- a possible miscarriage or blighted ovum
- an ectopic pregnancy
Levels of hCG that are higher than normal could mean:
- a miscalculation of pregnancy dating
- a molar pregnancy
- a multiple pregnancy, such as twins or triplets
Is the hCG blood test always
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 do follow-up testing if there’s
If an hCG test comes back negative, that generally means that 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. In a false-negative test result, the test indicates that a woman is not pregnant, when in fact she is. Because hCG levels change so quickly during early pregnancy, the hCG
quantitative 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 non-pregnant conditions, potentially causing a false-positive hCG pregnancy test. In a false-positive test result, the test indicates that a woman is pregnant, when in fact she is not. 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 is any doubt about
the results, a different testing method can be used to confirm.
Talk to your doctor
Don’t panic if your numbers don’t exactly match the “normal” levels.
These figures are estimates, and you can have hCG levels that are lower than
normal and still have a healthy baby. You’ll receive an ultrasound around six weeks which is considered much more accurate than your hCG numbers. If
there’s reason to be concerned about your pregnancy, multiple hCG readings done
a couple of days apart will be used to assess your situation.
Numbers can vary, so it’s important to listen to your doctor
concerning the health of your pregnancy. Your doctor will check your hCG levels
if they detect a problem. Ask questions if you’re concerned about something and
let them know immediately if you’re experiencing any problems.