A human chorionic gonadotropin (hCG) urine test is a pregnancy test. A pregnant woman’s placenta produces hCG, also called the pregnancy hormone. If you’re pregnant, the test can usually detect this hormone in your urine about 10 days after your first missed period. This is when the fertilized egg attaches to the uterine wall.
During the first eight to 10 weeks of pregnancy, hCG levels normally increase very rapidly. These levels reach their peak at about the tenth week of pregnancy, and then they gradually decline until delivery.
HCG urine tests are commonly sold in kits that you can use at home. The hCG urine test often is referred to as a home pregnancy test.
The hCG urine test confirms pregnancy about one to two weeks after your missed period. This is a qualitative test, which means that it will tell you whether or not it detects the hCG hormone in your urine. It’s not intended to reveal specific levels of the hormone. The presence of hCG in your urine is considered a positive sign of pregnancy.
The only risks associated with an hCG urine test involve getting a false-positive or false-negative result. A false-positive result indicates a pregnancy, even though there isn’t one. Rarely, the test may detect abnormal, non-pregnancy tissue, which requires follow-up by a doctor. These results are rare because usually only pregnant women produce the hCG hormone.
There’s a higher risk of getting a false-negative result. If you get a false-negative result, in which case the test says you aren’t pregnant but you really are, you might not take the precautions necessary to give your unborn baby the best possible start. Such results may occur more commonly in early pregnancy or if the urine is too diluted to detect hCG.
There are no special preparations necessary to take an hCG urine test. You can ensure the most accurate results with simple planning.
If you’re taking a home pregnancy test, you should do the following:
- Carefully read the instructions included in your test kit before collecting your urine sample.
- Make sure the test’s expiration date hasn’t passed.
- Look for the manufacturer’s toll-free number on the package, and call it if you have any questions about using the test.
- Use your first morning urine one to two weeks after your first missed period.
- Don’t drink large amounts of fluid before collecting your urine sample because this may dilute hCG levels and make them difficult to recognize.
Discuss any medications you’re taking with your pharmacist or doctor to see if they could affect the results of an hCG urine test.
Diuretics and an antihistamine called promethazine can cause false-negative results.
Anticonvulsants, drugs for Parkinson’s disease, hypnotics, and tranquilizers can cause false-positive results, which means they can indicate you’re pregnant when you’re not.
You can take an hCG urine test at your doctor’s office or at home with a home pregnancy test. Both will require the collection of a urine sample. An hCG urine test conducted at home is similar to the test that your doctor conducts. Both have the same ability to detect hCG in your urine.
Most hCG urine tests sold for home testing follow a similar procedure for accurate testing. While you should carefully follow the instructions included with your kit, the process typically follows these steps:
- Wait one to two weeks after your first missed period to get the most accurate results. Irregular periods or miscalculations of when a period is due can affect your test. In fact, 10 to 20 percent of pregnant women may not detect their pregnancy by testing on what they believe to be the first day of their first missed period, according to the U.S. Food and Drug Administration (FDA).
- Plan to use the test the first time you urinate after waking up. This urine is the most concentrated and will contain the highest hCG levels of the day. Your urine dilutes as you drink liquids, so hCG levels may be harder to measure later in the day.
- For some home pregnancy tests, you will hold an indicator stick directly in the urine stream until it’s soaked, which should take about five seconds. Other kits require that you collect urine in a cup and then dip the indicator stick into the cup to measure the hCG hormone level.
- Home pregnancy tests usually include an indicator that shows whether the test is being properly performed. For example, it will show if there’s enough urine on the stick to get an accurate result. If the control indicator doesn’t activate during your test, the results may be inaccurate.
- For most tests, it only takes about 5 to 10 minutes for a result to appear. Typically, a colored line or plus symbol will appear on the test stick to indicate a positive result. The absence of a colored line or a negative sign usually indicates a negative result.
The accuracy of your hCG urine test results will depend on your ability to closely follow the test kit’s instructions. If you have a negative result, you should consider these results to be uncertain, as they may indicate a false negative. Until you can be sure that you’re not pregnant, you should be cautious and avoid doing anything that could hurt a developing fetus. Smoking, using alcohol, and certain medications can harm your baby in early pregnancy.
A false-negative result can happen after any of the following:
- using a urine sample collected after your first morning urine
- taking the test before there’s enough hCG to produce a positive result
- miscalculating the timing of your missed period
If you have a negative result, you should repeat the test in about a week to confirm the absence of pregnancy. If you believe the tests are indicating a false negative and that you’re pregnant, you should consult your doctor. They can conduct an hCG blood test, which is more sensitive to lower levels of the hCG hormone than the hCG urine test.
If you have a positive result, it means that the test detected hCG in your urine. Your next step should be to consult your doctor. They can confirm pregnancy with an exam and additional testing, if necessary. Getting prenatal care early in your pregnancy gives your baby the best chance for healthy growth and development before and after birth.