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. Some just check to see if the hormone is present. HCG is
made by the placenta during pregnancy. The test can be used
to see if a woman is pregnant. Or it can be done as part of a screening test for birth
HCG may also be made by certain tumors, especially those that come
from an egg or sperm. (These are called germ cell tumors.) HCG levels are often tested
in a woman who may have tissue that is not normal growing in her uterus. The test
also may be done to look for molar pregnancy or a cancer inside the uterus.
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 if he has cancer of
to detect pregnancy
An egg is normally fertilized by a sperm cell in a fallopian tube. Within 9 days the fertilized
egg moves down the fallopian tube into the uterus. It then attaches (implants) to
the wall of the uterus. After the fertilized egg implants, the growing placenta starts
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. This can be as early
as 6 days after the egg implants.
HCG helps to keep your pregnancy going. It
also affects the development of your baby (fetus). Levels of hCG go up fast in the
first 14 to 16 weeks after your last menstrual period. They are the highest around
the 14th week following your last period. They then go down gradually. The amount
that hCG goes up 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 your blood.
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 ectopic pregnancy.
HCG blood tests
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. These tests are usually done
between 15 and 20 weeks of pregnancy to check the levels of three or four substances
in a pregnant woman's blood. The triple screen checks hCG, alpha-fetoprotein (AFP),
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 figure out the chance that the
baby may have certain problems or birth defects.
cases, screening tests are combined in the first trimester to look for Down syndrome. This screening
test uses an ultrasound to measure the thickness of the skin at the back of the fetus's
neck (nuchal translucency). It also includes a blood test for the levels hCG and a
protein called pregnancy-associated plasma protein A (PAPP-A). This test works about
as well as the second-trimester maternal serum quad screening.footnote 1
HCG urine tests
HCG urine tests are usually used for regular pregnancy testing.
The test does not measure the exact amount of hCG, but it shows if hCG is present.
Home versions of this test are easy to find and buy.
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A test for human chorionic gonadotropin (hCG) is done to:
if you are pregnant.
Find an ectopic pregnancy.
Find and check the
treatment of a molar pregnancy.
See if there is a greater chance of birth
defects such as Down syndrome. The test is done with other screening tests.
and check on the treatment of a cancer that develops from an egg or sperm (germ cell
cancer), such as cancer of the ovaries or testicles. In such cases, a test for alpha-fetoprotein
may be done along with a test for hCG.
How To Prepare
a blood sample is collected, you do not need to do anything before you have this test.
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 you
last urinated will also have high amounts of hCG.
How It Is Done
chorionic gonadotropin (hCG) may be measured in a sample of blood or urine.
Blood sample collection
The health professional
drawing blood will:
Wrap an elastic band around your upper arm to stop
the flow of blood. This makes the veins below the band larger so it is easier to put
a needle into the vein.
Clean the needle site with alcohol.
needle into the vein. If the needle is not placed correctly or if the vein collapses,
more than one needle stick may be needed.
Attach a tube to the needle to fill
it with blood.
Remove the band from your arm when enough blood is collected.
a gauze pad or cotton ball over the needle site as the needle is removed.
pressure on the site and then put on a bandage.
If possible, collect a sample from the first urine of the
Place the collection container into the stream of urine. Collect about4 Tbsp (60 mL) of urine.
Do not touch the rim of
the container to your genital area. And do not get toilet paper, pubic hair, stool
(feces), blood, or other foreign matter in the urine sample.
into the toilet or urinal.
Carefully replace the lid on the container. Return
it to the lab. If you are collecting the urine at home and can't get it to the lab
in an hour, refrigerate it.
How It Feels
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 you wait for results of an hCG test done to check the health of your baby.
In most cases, there is no pain with
collecting a urine sample.
Risks of a blood test
There is very little chance of a problem from having
a blood sample taken from a vein.
You may get a small bruise at the site.
You can lower the chance of bruising by keeping pressure on the site for several minutes.
rare cases, the vein may become swollen after the blood sample is taken. This problem
is called phlebitis. A warm compress can be used several times a day to treat this.
Collecting a urine sample does not cause
The human chorionic gonadotropin (hCG) test
is done to measure the amount of the hormone hCG in blood or urine to see if a woman
is pregnant. HCG may also be measured to see if cancer of the ovaries or testicles
These numbers are just
a guide. The range for "normal" varies from lab to lab. Your lab may have a different
range. Your lab report should show what range your lab uses for "normal." Also, your
doctor will evaluate your results based on your health and other factors. So a number
that is outside the normal range here may still be normal for you.
chorionic gonadotropin (hCG) levels in bloodfootnote 2
Pregnant women, 1 week of gestation
(about 3 weeks after the last menstrual period):
women, 2 weeks of gestation (about 4 weeks after the LMP):
women, 3 weeks of gestation (about 5 weeks after the LMP):
Pregnant women, 4 weeks of gestation (about 6 weeks after the
Pregnant women, 6-8 weeks of gestation
(about 8-10 weeks after the LMP):
women, 12 weeks of gestation (about 14 weeks after the LMP):
Pregnant women, 13-16 weeks of gestation (about 15-18 weeks
after the LMP):
levels in urine
None (negative test)
None (negative test)
you are pregnant, very high levels of hCG can mean a multiple pregnancy (such as twins
or triplets). It can also mean a molar pregnancy or Down syndrome. You may also be further along
in an early pregnancy than you thought, based on your last menstrual period.
a man or a nonpregnant woman, a high hCG level can be a sign of a tumor (cancerous
or noncancerous). These tumors can develop from a sperm or egg cell (germ cell tumor),
such as a tumor of the testicles or ovaries. It may also mean some types of cancer,
such as cancer of the stomach, pancreas, large intestine, liver, or lung.
If you are pregnant, a low level
of hCG can mean an ectopic pregnancy or a miscarriage. It may also
mean that you aren't as far along in an early pregnancy as you thought, based on your
last menstrual period (LMP).
If you are pregnant, levels of hCG that are going
down abnormally can mean a miscarriage (spontaneous abortion) is very likely.
Affects the Test
You may not be able to have the test, or the results may not
be helpful, if:
You do your urine test for hCG very early in pregnancy
(during the first week after implantation) or on a urine sample taken in the middle
of the day. The test may not always show an early pregnancy.
You have had
a miscarriage (spontaneous abortion) or therapeutic abortion. HCG results may stay
high (positive) for up to 4 weeks after a miscarriage or therapeutic abortion.
got an injection of hCG to treat infertility. This may cause test results to appear
high for several days after the injection.
There is blood in the urine sample
or soap in the collecting container. These can change the hCG level.
diuretics or promethazine. These medicines can
cause false low hCG levels in urine test results.
You use heparin, a medicine
to prevent blood from clotting (anticoagulant).
You use certain medicines.
These include hypnotics (such as Ambien), antipsychotics, and antinausea medicines
(such as prochlorperazine). Be sure to tell your doctor what medicines you take.
To Think About
Home pregnancy tests that find hCG in urine are easy to
find and buy. To learn more, see the topic Home Pregnancy Tests.
A blood test for hCG is generally more accurate
than a urine test. If you still think you're pregnant even after your urine test results
do not show a pregnancy (negative results), you can try a blood test. Or you can repeat
the urine test in a week.
A normal hCG value does not rule out the possibility
of a tumor in the uterus, ovaries, or testicles. HCG is only one part of a group of
tests when a tumor is suspected.
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
Other Works Consulted
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.
ByHealthwise Staff Primary
Medical ReviewerSarah A. Marshall, MD - Family Medicine E. Gregory Thompson, MD - Internal Medicine Adam
Husney, MD - Family Medicine Kathleen Romito,
MD - Family Medicine Siobhan M. Dolan, MD, MPH
- Reproductive Genetics Rebecca Sue Uranga, MD
- Obstetrics and Gynecology
This information does not replace the advice of a doctor.
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