How to Take the Most Accurate Pregnancy Test
After a fertilized egg implants in your uterine lining, it starts creating a pregnancy hormone known as human chorionic gonadotropin (hCG) At-home pregnancy tests work by detecting trace amounts of hCG in your urine. They're relatively inexpensive, and they can be found at most drug stores and grocery stores. Are you wondering how to take a pregnancy test to get the most accurate results possible? Read our guide for everything you need to know.
Types of Pregnancy Tests
There are two main types of at-home pregnancy tests: digital and non-digital.
Non-Digital Pregnancy Tests: These tests come in many different forms, including standard sticks and test strips. Usually women must pee directly on sticks, while test strips should be dipped in a cup of urine. (Always read the packaging of your pregnancy test for your brand's specific instructions though.) Either way, the urine must soak on the pregnancy test for several minutes, and the results will appear on a screen.
Pregnancy tests contain antibodies coated with a chemical that bonds to hCG if it's present, delivering a positive result. Depending on your specific test, positive results are usually indicated by a plus sign, a faint line, or a color change. If the molecules do not bond with any hCG, you get a negative result.
Digital Pregnancy Tests: Digital tests look like a pen-shaped instrument instead of a traditional stick, and they rely on a method called "rapid assay delivery," which might give results in only three minutes. This method combines a biochemical process with antibodies that detect hCG. With digital tests, there is no guesswork or wondering Is that a line? or Is that a color? A digital at-home test will simply say "pregnant" or "not pregnant." While digital tests are available at grocery stores and drug stores, they tend to be a little bit more expensive.
How Long Should You Wait to Take a Pregnancy Test?
No matter what type of pregnancy test you choose, timing is key to getting accurate results. After conception, it takes a while for hCG to generate in your body. Sometimes hCG reaches detectable levels before missing your period—but sometimes it doesn't, says Daniel Roshan, M.D., an OB-GYN at Rosh Maternal-Fetal Medicine in New York City.
Because hCG levels double every 48 to 72 hours, according to Dr. Roshan, taking a pregnancy test after missing your period gives you a greater likelihood of accuracy. For those with irregular periods, a good rule of thumb is waiting three weeks after having sex.
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Most manufacturers recommend that home pregnancy tests be taken twice, since results may vary if you take a test too soon. In some cases, if your hCG levels are too low to catch early on, you may get a false negative result. This is especially common if you take "early detection" tests that promise results three, four, or even five days before a missed period.
Are Pregnancy Tests Accurate?
Pregnancy tests are about 99 percent accurate when used correctly. It's possible to get false negative results (when you're actually pregnant but the test says you aren't). The most common cause is taking the test too early, but it can also happen if you don't follow instructions. If you missed your period and it doesn't arrive after a few days, repeat the test or check with your doctor, suggests Marra Francis, M.D., a board-certified obstetrician and gynecologist. Irregular periods could be caused by illness, certain medications, low body weight, excessive exercise, stress, or hormonal contraceptives.
Even rarer, it's possible to get false positive results (you're not pregnant but the test says you are). While false positives mainly happen to women taking fertility drugs, they can also be caused by an expired pregnancy test, recent miscarriage or abortion, pregnancy loss soon after implantation (chemical pregnancy), or ovarian tumors.
Here are some tips for increasing the accuracy of your pregnancy test:
- Check the pregnancy test's expiration date before purchasing it. If it's expired, it may not work properly.
- Many doctors recommend taking the test first thing in the morning, as the concentration of hCG in your urine is usually highest then.
- Despite common misconception, you shouldn't chug liquids before taking a pregnancy test. Doing this can dilute hCG levels in your urine and lead to a false negative result.
- Some medications, like prescription fertility drugs, might mess up the pregnancy test. Your doctor may recommend getting tested in the office for more promising results.
- Improper usage and exposure to sunlight may also lead to inaccurate results. Always use the pregnancy test according to instructions.
The Pregnancy Test Is Positive—Now What?
If your test says that you're pregnant, you're probably expecting a baby! The next step is calling your doctor, who will likely schedule an appointment about eight weeks after your last period to confirm your pregnancy with a transvaginal ultrasound. For many women, a pregnancy blood test is not needed.