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Pregnancy Test Guide

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on June 24, 2022.


  • There are two different types of pregnancy tests: those that check your blood and those that check your urine.
  • The pregnancy blood (serum) test must be performed at a doctor’s office or clinic, but the urine test can be performed at home or in a clinic. Home urine tests are readily available at pharmacies and other retail outlets.
  • Both urine and blood pregnancy tests detect the presence of the hormone human chorionic gonadotropin (hCG). The hCG hormone is usually only present in blood or urine if a woman is pregnant.
  • Be sure you read and follow the package instructions exactly.

Many woman like the convenience and privacy of using an at home urine pregnancy test to initially determine if they are pregnant or not. Home pregnancy tests are very accurate (if used properly), inexpensive and easily available at the pharmacy or grocery store. Most only take about 10 minutes to see the results.

If a pregnancy test is found to be positive, or if it is negative but you still suspect you might be pregnant, you should contact your health care provider.

What early pregnancy symptoms or pregnancy signs may occur?

The first sign of pregnancy that many women experience is a missed menstrual cycle (their period). Other early symptoms of pregnancy or signs of pregnancy might be:

  • nausea and vomiting (or morning sickness, which can really happen at any time of the day or night)
  • tender or swollen breasts
  • increased urination, especially at night
  • fatigue and tiredness
  • food distastes or food cravings

How do pregnancy tests work and how are they be used?

All pregnancy tests work by detecting the presence of human chorionic gonadotropoin (hCG), the pregnancy hormone.

When an egg fertilized with sperm is implanted in the uterus of the woman the hCG hormone is then produced. The egg usually implants into the wall of the uterus about six days after fertilization, but in about 10% of women implantation may not occur until after the first day of the missed period. The levels of hCG rise in the body early in pregnancy after implantation occurs.

How accurate are home pregnancy tests?

While many early detection pregnancy tests claim to be 99% accurate even one day after a missed period, results can be variable.

  • In up to 10% of women, implantation may not occur until after the first day of the missed period, in which case hormone levels of hCG may not be high enough to be detected by the test.
  • However, research shows that most home pregnancy tests can detect hCG accurately one week after a missed period.
  • Also, testing with your first urination in the morning is more likely to have higher amounts of hCG in the sample and may give you a more accurate result.

A quantitative blood pregnancy test done at the doctor’s office (also known as the beta hCG test) can detect low levels of hCG and measure the actual quantity of hCG in your body. This test may be the most accurate option if you need a pregnancy test very early. Women should contact their physician if they prefer the beta hCG blood test.

If a negative pregnancy result occurs with a home urine test, the test should be repeated in a few days to a week to confirm the negative result. Women with positive pregnancy tests should contact their healthcare providers.

Before a home pregnancy test is purchased, the expiration date should be checked on the outside of the packaging. If the expiration date is passed, do not buy or use the pregnancy test.

Check the expiration date, read the instructions, and follow the specific directions for each home pregnancy test package. While home pregnancy tests work in the same way by detecting hCG in the urine, the specific directions for use may vary from test to test. Be sure to read and follow the instructions exactly.

Store unopened tests in a cool, dry place.

How to read the results on your home pregnancy test

Some tests instruct the user to hold the test stick in the stream of urine, while others involve dipping the stick or pregnancy test strips into a cup of collected urine. Be sure you wait the correct number of minutes outlined on the package directions before you read the results.

Most urine pregnancy tests have a “control” window and another window that is the “results” window. When this line or other symbol appears in the control window it ensures that the test is working properly. If a control window does not show a line or other symbol as indicated by the package instructions, then the test is not working properly. A new pregnancy test should be used the next morning.

  • If the control window is working properly, and a line, plus sign, or other symbol as directed by the package instructions appears in the results window, this means the test is positive and the woman is pregnant. For positive results, the woman should contact her physician to make an appointment as soon as possible for next steps.
  • If no symbol appears in the window as directed by the instructions, then the results are most likely negative. However, it is best to confirm the results of a negative test by repeating it in a few days.
  • A faint symbol on the pregnancy test window is usually still positive but may mean that the levels of hCG in the blood are are still quite low. If you are concerned about a faint line on a pregnancy test, it is best to wait a few days and repeat the test, or contact a physician for a confirmatory blood test.

Some digital pregnancy tests now have a digital display window that will report the results in words, such as “pregnant” or “not pregnant”. Digital pregnancy tests may not have a control window, but may show a flashing symbol in the window prior to the result.

Most home pregnancy tests come with a toll-free number to call if the woman has questions.

Where can I get a home pregnancy test and how much will it cost?

Home pregnancy tests are readily available without a prescription and most are very affordable.

  • Home pregnancy tests can be bought without prescriptions at most pharmacies, grocery stores and larger retail chains.
  • You can also buy a pregnancy test over the Internet, but be cautious and buy from a reputable online retailer. Always check the expiration date on the package once the test is received and before you use it.
  • If the expiration date has passed, do not open the test and return it for a refund.

Common names of at home pregnancy tests include:

  • First Response Manual or Digitial
  • Accu-Clear
  • Clearblue Rapid
  • Clearblue Manual or Digital
  • Clearblue Fact Plus
  • Easy Home
  • EPT manual and digital
  • Natalist
  • Pregmate

On average, home pregnancy tests cost between $5 and $25 depending upon the brand and contents. Many packages may also contain more than one test, which drive up the costs. However, if you suspect you might be pregnant even if your test result is negative, repeat the test in one week. Brand name home pregnancy tests are available in addition to the less expensive "store brands".

If you get a urine pregnancy test in the doctor's office or clinic, it may be more expensive using your insurance for payment or paying cash than using an at-home test.

Where can I get a free pregnancy test?

You may be able to get a free pregnancy test at certain health centers in your community. You might want to call your county health clinic or local Planned Parenthood. Also, ask your nurse or doctor for recommendations.

Which pregnancy test is best?

There is no one answer to this question. All home pregnancy tests should give accurate results if not expired and the directions are followed closely. Many home tests claim to be 99% accurate on the first day of the missed period, but some studies refute this claim.

In one study, researchers compared six home pregnancy tests.

  • They found that the hCG sensitivity of the First Response manual and First Respone digital pregnancy tests was 5.5 mlU/mL, while the sensitivity of the EPT and Clear Blue brand was 22 mlU/mL. According to the authors, both First Response tests detected 97% of 120 pregnancies on the day of the missed period. First Response also ranks 4.5 / 5 stars by over 27,000 consumers in a common online retailer.
  • The EPT manual and digital devices detected 54% and 67% of pregnancies, respectively, and the Clear Blue manual and digital devices detected 64% and 54% of pregnancies, respectively, on the first day of the missed period. However, other studies have found a greater than 90% accuracy for the ClearBlue tests.

Ultimately, following the package instructions and waiting at least a week after the first day of your missed period will give you the most accurate results for all tests. If you receive a negative pregnancy test, it's always best to test again in a few days to confirm the results.

What is a false positive pregnancy test or a false negative pregnancy test?

  • A false positive is when the results of the pregnancy test indicate that the woman is pregnant, but in fact she is not.
  • A false negative pregnancy test is when the results of the test indicate that the woman is not pregnant, but she actually is pregnant.
  • A false-negative is much more likely to occur than a false-positive.

What can cause a false positive pregnancy test?

In rare circumstances, the hCG hormone may be present in the body when a woman is not pregnant and may lead to a pregnancy test false positive result.

Some infertility medications (medications that are used when a woman is having trouble getting pregnant) may cause a false-positive because they contain hCG. Other circumstances that can lead to a false positive include:

  • ovarian cysts
  • recent pregnancies
  • pregnancy loss soon after a fertilized egg implanted (biochemical pregnancy)
  • an ectopic pregnancy
  • a molar pregnancy
  • menopause

What can cause a false negative pregnancy test?

Reasons for a false negative pregnancy test may include:

  • performing the test too early before adequate hCG hormone levels rise
  • timing the test wrong (checking on the results too early)
  • using a dilute urine

To help avoid false negative results, wait for one week after a missed period to use the pregnancy test, use a timer or stopwatch to increase pregnancy test accuracy, and use the first urine of the morning for the test, when the concentration of hCG is at its highest level.

If you continue to get negative test results, but you think you might be pregnant or your period does not start, contact your doctor. There are several other medical conditions that may lead to loss of a period, such as heavy exercise or thyroid problems.

Can medicine or alcohol interfere with the results of a home pregnancy test?

  • Most medications, including birth control pills and antibiotics, do not interfere with pregnancy test results.
  • Alcohol and illegal drugs, such as marijuana, cocaine or heroin may not interfere with the results of a pregnancy test, but these substances should not be used if a woman is trying to conceive, is pregnant or is sexually active without a reliable form of birth control.

Learn More: See the Female Infertility Guide


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  2. Mayo Clinic Staff. Getting Pregnant. Home pregnancy tests: Can you trust the results? Accessed June 26, 2022 at
  3. Johnson S, Cushion M, Bond S, Godbert S, Pike J. Comparison of analytical sensitivity and women's interpretation of home pregnancy tests. Clin Chem Lab Med. 2015;53(3):391-402. June 26, 2022 at doi:10.1515/cclm-2014-0643. 
  4. Pregnancy Test. Planned Parenthood. Accessed July 1, 2020 at
  5. Pregnancy Test. What you need to know. Feb. 28, 2018. June 26, 2022 at

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.