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Home > Wellness > Health Library > Human Chorionic Gonadotropin (HCG)
The human chorionic gonadotropin (hCG) test is
done to check for the
hormone hCG in blood or urine. Some hCG tests measure
the exact amount and some just check to see if the hormone is present. HCG is
made by the
placenta during pregnancy. The hCG test can be used to
see if a woman is pregnant or as part of a screening test for birth
HCG may also be made abnormally by certain tumors,
especially those that come from an egg or sperm (germ cell tumors). HCG levels
are often tested in a woman who may have abnormal tissue growing in her uterus,
molar pregnancy, or a cancer in the uterus
(choriocarcinoma) rather than a normal pregnancy. Several hCG tests may be done
after a miscarriage to be sure a molar pregnancy is not present. In a man, hCG
levels may be measured to help see whether he has cancer of the
An egg is normally fertilized by
a sperm cell in a
fallopian tube. Within 9 days after
fertilization, the fertilized egg moves down the
fallopian tube into the uterus and attaches (implants) to the uterine wall.
Once the fertilized egg implants, the developing placenta begins releasing hCG
into your blood. Some hCG also gets passed in your urine. HCG can be found in
the blood before the first missed menstrual period, as early as 6 days after
HCG helps to maintain your pregnancy and affects the
development of your
baby (fetus). Levels of hCG increase steadily in the
first 14 to 16 weeks following your last menstrual period (LMP), peak around
the 14th week following your LMP, and then decrease gradually. The amount that
hCG increases early in pregnancy can give information about your pregnancy and
the health of your baby. Soon after delivery, hCG can no longer be found in
More hCG is released in a multiple pregnancy, such as
twins or triplets, than in a single pregnancy. Less hCG is released if the
fertilized egg implants in a place other than the uterus, such as in a
fallopian tube. This is called an
HCG blood tests can be used to see
if hCG is present but they can also measure the exact amount of hCG in the
blood. A blood test can be used to see if a woman is pregnant, to check for
abnormal pregnancies, or to test for hCG related to certain cancers.
The level of hCG in the blood is often used as part of a screening for
birth defects in a maternal serum triple or quadruple screening test. Generally
done between 15 and 20 weeks, these tests check the levels of three or four
substances in a pregnant woman's blood. The triple screen checks
alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and a type of
estrogen (unconjugated estriol, or uE3). The quad screen checks these
substances and the level of the hormone inhibin A. The levels of these
substances—along with a woman's age and other factors—help the doctor estimate
the chance that the baby may have certain problems or birth defects.
In some cases a combination of screening tests is done in the first
trimester to look for Down syndrome. This screening
test uses an ultrasound measurement of the thickness of the skin at the back of
the fetus's neck (nuchal translucency), plus a blood test of the levels of the
pregnancy hormone hCG and a protein called pregnancy-associated plasma protein
A (PAPP-A). This test is about as accurate as the second-trimester maternal
serum quad screening.1
HCG urine tests are usually used
for routine pregnancy testing. The test does not measure the exact amount of
hCG, but it shows if hCG is present. Home pregnancy tests that show hCG in
urine are also widely available.
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A test for human chorionic gonadotropin
(hCG) is done to:
If a blood sample is collected, you do
not need to do anything before you have this test.
If a urine test
is done, the first urine of the day is generally the best to use because it has
the highest level of hCG. A urine sample collected at least 4 hours after
the last urination will also have high amounts of hCG.
Human chorionic gonadotropin (hCG) may
be measured in a sample of blood or urine.
The health professional
drawing blood will:
If possible, collect a sample
from the first urine of the day (this urine generally has the highest level of
hCG). A urine sample collected at least 4 hours after the last urination
will also have high amounts of hCG.
The blood sample is taken from a vein
in your arm. An elastic band is wrapped around your upper arm. It may feel
tight. You may feel nothing at all from the needle, or you may feel a quick
sting or pinch.
You may feel anxious while awaiting results of an
hCG test done to check the health of your baby.
There is normally no discomfort with
collecting a urine sample.
There is very little chance
of a problem from having a blood sample taken from a vein.
There is no chance for problems while
collecting a urine sample.
The human chorionic gonadotropin (hCG)
test is done to measure the amount of the
hormone hCG in blood or urine to see whether a woman
is pregnant. HCG may also be measured to see whether cancer of the ovaries or
testicles is present.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
international units per liter (IU/L)
Pregnant women, 1 week of gestation (about 3 weeks after
the last menstrual period):
Pregnant women, 2 weeks of gestation (about 4 weeks after the
Pregnant women, 3 weeks of gestation (about 5 weeks after the
Pregnant women, 4 weeks of gestation (about 6 weeks after the
Pregnant women, 6–8 weeks of gestation (about 8–10 weeks after the
Pregnant women, 12 weeks of gestation (about 14 weeks after
Pregnant women, 13–16 weeks of gestation (about 15–18 weeks after
Up to 200,000
Things that may affect the
results of your test include:
American College of Obstetricians and Gynecologists
(2007, reaffirmed 2008). Screening for fetal chromosomal abnormalities. ACOG Practice Bulletin
No. 77. Obstetrics and Gynecology, 109(1): 217–227.
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Wapner RJ, et al. (2009). Prenatal diagnosis of congenital disorders. In RK Creasy et al., eds., Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice, 6th ed., pp. 221–274. Philadelphia: Saunders Elsevier.
Current as of:
June 4, 2014
Sarah Marshall, MD - Family Medicine & Siobhan M. Dolan, MD, MPH - Reproductive Genetics
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