What Is a Pregnancy Test?

A pregnancy test checks your pee or blood to see if you're pregnant.

There are different reasons you might take a pregnancy test. Maybe you're trying to get pregnant and you want a positive result. Or maybe something interrupted your birth control. You also might take a pregnancy test before having a medical procedure or starting a new medication, to avoid complications. This is true whether you're biologically female, nonbinary, or transgender male. If you have a uterus and ovaries (and you're ovulating), and you’re having penetrative sex with a penis, you can get pregnant.

Here are the answers to some common questions about pregnancy tests.

LH Ovulation Test Strip

How Do Pregnancy Tests Work?

Pregnancy tests check your pee or blood for a hormone called human chorionic gonadotropin (HCG). Your body makes this hormone when you're pregnant and a fertilized egg attaches to the wall of your uterus.

This usually happens about 6 days after fertilization. Levels of HCG rise quickly, doubling every 2 to 3 days.

Types of Pregnancy Tests

Two main types of pregnancy tests are blood tests and urine tests.

Pregnancy blood tests

You get these at your doctor's office, but they’re not used as often as urine tests. That's because they can be costlier and have the same results. But blood tests can detect pregnancy earlier than a home pregnancy test, about 7-10 days after ovulation. Results take 2 hours to 2 days.

A blood pregnancy test uses a small sample of your blood from a vein in your arm. It detects the presence and amount of the pregnancy hormone in your body. That's helpful when your doctor needs to know the exact amount of HCG in your blood, and not just if it's present in your blood.

You might get a blood test for pregnancy if you're having fertility treatments or if your doctor thinks there might be a problem.

The two types of blood pregnancy tests are:

1. A qualitative hCG test simply checks for hCG. It gives a “yes” or “no” answer to the question, “Are you pregnant?” Doctors often order these tests to confirm pregnancy as early as 10 days after conception. Some can detect hCG much earlier.
2. A quantitative hCG test (beta hCG) measures the exact amount of hCG in your blood. It can find even very low levels of hCG. These tests may help track problems during pregnancy. Your doctor may use them along with other tests to rule out an ectopic pregnancy when the fertilized egg implants outside your uterus, or after a miscarriage when hCG levels fall quickly.

3. Pregnancy urine tests

   You can take these at home or in a doctor's office.

   Along with being private and convenient, home pregnancy tests are quick and easy to use. They’re also very accurate if you follow the directions. These pregnancy tests all work in a similar way. You test your pee in one of these ways:

   • Hold the test stick in your urine stream
   • Collect pee in a cup and dip the test stick into it
   • Collect pee in a cup and use a dropper to put it into another container

   You’ll need to wait a few minutes before seeing the results.

   After you take this test, confirm your results by seeing your doctor.

   Pregnancy Test Accuracy

   Urine home pregnancy tests are about 99% accurate. Blood tests are even more accurate.

   A home test’s accuracy depends on:

   • How closely you follow the instructions
   • When you ovulate and how soon the egg implants
   • How soon after pregnancy you take the test
   • The sensitivity of the pregnancy test