How to read hcg pregnancy test

A pregnancy test measures a hormone in the body called human chorionic gonadotropin (hCG). hCG is produced during pregnancy and found in the blood and urine.

Testing for hCG can be used as soon as 10 days after conception to help determine if a person is pregnant. Measuring hCG can also help identify complications during pregnancy.

The standard use for a pregnancy test is to evaluate if a person is pregnant. Both urine and blood tests for hCG can be used for this purpose, and repeat testing may be done to confirm a pregnancy. Very early in a pregnancy, tests that measure the amount of hCG may also help assess the age of a fetus.

Less often, hcG tests can be used to:

• Identify or rule out an ectopic pregnancy, which is when a fertilized egg attaches or implants in an abnormal area
• Check for pregnancy prior to surgery or other medical treatments
• Screen for Down syndrome in pregnant people as part of prenatal screening
• Monitor a pregnancy that may be at risk of a miscarriage
• Help diagnose gestational trophoblastic disease (GTD), which is a term for pregnancy-related tumors.

What does the test measure?

A pregnancy test measures a hormone in the body called human chorionic gonadotropin (hCG). hCG is created at higher levels during pregnancy. There are two different ways hCG results are reported:

• Qualitative: Qualitative hCG tests give a positive or negative result depending on the presence or absence of hCG in the sample. Qualitative tests can be done using either a blood or urine sample. This type of testing is done most often to confirm a pregnancy.

• Quantitative: Quantitative hCG testing measures the amount of hCG present in the blood. These tests frequently use a blood sample, but some urine tests can provide a degree of quantitative measurement. Along with confirming a pregnancy, quantitative hCG tests can also be used as part of the diagnostic process for abnormal pregnancies and other health conditions not related to pregnancy that can raise hCG levels. 

When should I get a pregnancy test?

A pregnancy test is most commonly done when a person is believed to be pregnant. Testing may detect a pregnancy as soon as 10 days after conception. The accuracy of pregnancy tests usually increases if taken at least 1-2 weeks after a missed menstrual period.

It may also be done when there are signs and symptoms that suggest an ectopic pregnancy or a pregnancy that is failing.

Signs of an ectopic pregnancy may include:

• Abnormal vaginal bleeding
• Low back pain
• Pain in the lower abdomen or pelvic area
• Cramping on one side of the pelvis

Additional and more severe symptoms may develop if an ectopic pregnancy is not identified and treated, so it is important for females of childbearing age to talk with a doctor if they notice these symptoms.

Pregnancy testing may also be done as a routine test prior to some medical treatments, such as surgeries or chemotherapy, that could potentially harm a fetus.

For any specific patient, a doctor is in the best position to determine if a pregnancy test is appropriate.

Laboratory tests such as blood draws and urine samples generally need to be ordered by a health care professional. Either of these tests can take place in the doctor’s office, hospital, or another laboratory. Urine tests can also be taken at home. If you suspect you are pregnant, talk with your health care professional about how to get a pregnancy test.

Can I take the test at home?

At-home pregnancy tests are a fast and convenient way to take a pregnancy test. Home pregnancy testing is very similar to qualitative urine hCG testing performed in the laboratory, but there are some important differences to be aware of:

• At-home tests have very specific instructions that must be followed exactly. When using an at-home test, follow the directions carefully. Each test’s ability to detect the presence of hCG can vary based on the brand of the test.
• You need to look carefully at the test instructions about how long you must wait to test after a missed menstrual period. Tests that are done too soon may result in a negative result when you are actually pregnant.
• At-home pregnancy tests should typically be done using a urine sample taken the first time you urinate in the morning. This is when urine is the most concentrated and has enough hCG to be detected.

When used correctly, most at-home pregnancy tests produce the same result as the qualitative urine hCG test done by a medical provider.

If your test is positive, it is important to reach out to your health care provider to learn more about the next steps in your care, including other tests that may be needed to confirm that you are pregnant.

How much does the test cost?

The cost of pregnancy testing depends on several factors, including a person’s insurance coverage, the type of pregnancy test, and where the test is performed.

If the pregnancy test is ordered by a doctor, insurance normally covers most of the cost, except for copays and deductibles. It’s important to check with your health insurance and health care provider for more information about specific costs.

A pregnancy test is done using blood or urine samples.

• A blood test is done by drawing a tube of blood from a vein in your arm. This is done in the doctor’s office, and the sample is sent to the laboratory.
• A urine test is done by urinating into a cup and then placing a drop of urine on a prepared chemical strip. This can be done in a doctor’s office or at home using an at-home test kit.

Before the test

You usually do not need to fast or do any special preparations before a urine or blood pregnancy test. However, you should always ask your doctor to clarify or confirm any pretest instructions.

During the test

When a pregnancy test is conducted in a medical facility or lab, a health care professional will instruct you on whether a blood sample or a urine sample will be needed.

If a blood sample is needed, it will be taken with a needle inserted into a vein in your arm. Before drawing the blood, an elastic band is tied around your upper arm to increase blood in the veins. The puncture location is then wiped clean and disinfected. A needle blood draw may cause a brief sting but normally lasts less than a minute.

To collect a urine sample, you urinate into a sterile cup given to you by your health care provider. In most cases, a urine sample taken the first time you urinate in the morning is best. Collecting a urine sample normally takes only a few minutes.

After the test

When the blood draw is completed, a band-aid or cotton swab will be used to prevent bleeding. You will likely be advised to keep the band-aid on for an hour or more.

Providing a urine sample does not require any post-test instructions or restrictions.

The time it takes to get the results of a pregnancy test depends on the type of test that is ordered. It may take anywhere from a few hours to more than a day to get the results of a blood test. Results from urine tests are generally available in one to two minutes.

Because both of these tests are generally done in a clinic setting, you will likely receive the results from a health care professional.

Interpreting test results

How pregnancy tests are reported depend on whether the test was qualitative or quantitative.

Qualitative test results

Qualitative test results are reported as positive or negative:

• A negative test result indicates that the patient is likely not pregnant. It is important to remember that tests performed too early can result in a false-negative result due to low levels of hCG. The test may need to be repeated in a week if there is a likely possibility of pregnancy.

• A positive result indicates that the patient is likely pregnant. False-positive results can occur in people who are post-menopausal or taking hormone supplements.

Quantitative test results

Quantitative test results are reported in milli-international units per milliliter (mUI/mL). hCG should not be detectable in people who are not pregnant. In pregnant people, hCG doubles approximately every 2-3 days during the first 30 days of the pregnancy. The level of hCG keeps rising throughout the first trimester and declines slowly during the second and third trimesters.

The results of quantitative test results may also be considered if hCG testing is being done related to an abnormal pregnancy or other health conditions.

Talking with a health care professional is the best way to learn more about your test results and the next steps in your care.

Are test results accurate?

While no test is 100% accurate, pregnancy tests are considered to be very accurate.

A positive result in someone who is not actually pregnant can occur after menopause or when taking hormone supplements. A negative result in someone who is actually pregnant can occur when a test is done too early after conception, when insufficient hCG levels are present. If a negative test occurs when a pregnancy is suspected, the test should be repeated a week later.

Sources

A.D.A.M. Medical Encyclopedia. Venipuncture.  Updated April 26, 2019. Accessed August 23, 2021. https://medlineplus.gov/ency/article/003423.htm

A.D.A.M. Medical Encyclopedia. Ectopic pregnancy.  Updated January 27, 2020. Accessed August 23, 2021. https://medlineplus.gov/ency/article/000895.htm

A.D.A.M. Medical Encyclopedia. Gestational trophoblastic disease.  Updated March 31, 2020. Accessed August 23, 2021. https://medlineplus.gov/ency/article/007333.htm

A.D.A.M. Medical Encyclopedia. HCG blood test – qualitative.  Updated December 2, 2020. Accessed August 21, 2021. https://medlineplus.gov/ency/article/003509.htm

A.D.A.M. Medical Encyclopedia. HCG in urine. Updated December 2, 2020. Accessed August 21, 2021. https://medlineplus.gov/ency/article/003619.htm

A.D.A.M. Medical Encyclopedia. Miscarriage. Updated December 2, 2020. Accessed August 23, 2021. https://medlineplus.gov/ency/article/001488.htm

A.D.A.M. Medical Encyclopedia. HCG blood test – quantitative. Updated December 3, 2020. Accessed August 21, 2021. https://medlineplus.gov/ency/article/003510.htm

A.D.A.M. Medical Encyclopedia. Pregnancy test. Updated December 3, 2020. Accessed August 8, 2021. https://medlineplus.gov/ency/article/003432.htm

ARUP Consult. hCG Testing. Updated October 2020. Accessed August 21, 2021. https://arupconsult.com/content/hcg-testing

Barbieri RL. Lab interpretation: Positive hCG in women. In: Schreiber CA, ed. UpToDate. Updated April 3, 2020. Accessed August 21, 2020. https://www.uptodate.com/contents/positive-hcg-in-women

Bastian LA, Brown HL. Clinical manifestations and diagnosis of early pregnancy. In: Lockwood CJ, ed. UpToDate. Updated September 8, 2020. Accessed August 26, 2021. https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-early-pregnancy

Dulay, AT. Ectopic pregnancy. Merck Manual Consumer Edition. Updated October 2020. Accessed August 23, 2021. https://www.merckmanuals.com/home/women-s-health-issues/complications-of-pregnancy/ectopic-pregnancy

Haninger-Vacariu N, Herkner H, Lorenz M, et al. Exclusion of pregnancy in dialysis patients: diagnostic performance of human chorionic gonadotropin. BMC Nephrol. 2020;21(1):70. Published 2020 Feb 28. doi:10.1186/s12882-020-01729-5

Harvey RA. Human chorionic gonadotropin: Biochemistry and measurement in pregnancy and disease. In: Goff B, ed. UpToDate. Updated July 16, 2021. Accessed August 26, 2021. https://www.uptodate.com/contents/human-chorionic-gonadotropin-biochemistry-and-measurement-in-pregnancy-and-disease

Office of Women’s Health. Pregnancy tests. Updated January 31, 2019. Accessed August 21, 2021. https://www.womenshealth.gov/a-z-topics/pregnancy-tests

Prager S, Micks E, Dalton VK. Pregnancy loss (miscarriage): Clinical presentations, diagnosis, and initial evaluation. In: Barbieri RL, Schreiber CA, Levine D, eds. UpToDate. Updated July 9, 2021. Accessed August 26, 2021. https://www.uptodate.com/contents/pregnancy-loss-miscarriage-clinical-presentations-diagnosis-and-initial-evaluation

Shields AD. Pregnancy diagnosis. Karjane NW, ed. Medscape. Updated March 28, 2017. Accessed August 24, 2021. https://emedicine.medscape.com/article/262591-overview#a3

US Food and Drug Administration. Pregnancy. Updated April 29, 2019. Accessed August 26, 2021. https://www.fda.gov/medical-devices/home-use-tests/pregnancy