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.
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:
- 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.
- 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.
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
When to Take a Pregnancy Test
Some pregnancy tests can spot hCG before you miss a period. But the results will be more accurate if you wait until the first day of a missed period.
Results may also be more accurate if you do the test first thing in the morning when your urine is more concentrated.
Home Pregnancy Tests
These are urine tests described in a section above. Here is some more information about them:
Where to buy a pregnancy test. They're available in most drugstores, pharmacies, convenience stores, and grocery stores. Some dollar stores sell them. Some can be mail-ordered.
Pregnancy test price. Their cost varies, but they usually cost about $50 each. Some insurance plans cover the cost. You can also save money per test if you buy them in bulk.
Tips for taking at-home pregnancy tests. Some tips for taking home pregnancy tests are:
- Use your first morning pee. This is when your HCG levels are most concentrated and easily detected.
- Don’t drink a lot of fluids before you take the test. This can dilute your HCG levels.
- Make sure your test isn't past its expiration date.
- Read the test's directions and follow them exactly.
Pregnancy Test Results
Results may show up as a line, a color, or a symbol such as a “+” or “-” sign. Digital tests show the words “pregnant” or “not pregnant.” It's important to know what a positive or negative result means.
If you get a positive result, you’re pregnant. This is true no matter how faint the line, color, or sign is. If you get a positive result, you may want to call your doctor to talk about what comes next.
False-positive results happen in very rare cases. This means you're not pregnant but the test says you are. You could have a false-positive result if you have blood or protein in your pee. Certain drugs, such as tranquilizers, anticonvulsants, hypnotics, and fertility drugs, could cause false-positive results.
If you get a negative result, you’re probably not pregnant. But you may be pregnant if:
- The test is past its expiration date.
- You took the test the wrong way.
- You tested too soon.
- Your pee is too diluted because you drank a lot of fluids right before the test.
- You’re taking certain medications, such as diuretics or antihistamines.
If you get a negative result, try retesting within about a week to double-check. Some home pregnancy tests suggest doing this no matter what your first results are.
False-negative results might happen if you take the pregnancy test too early. The earlier you take it, the harder it is to detect HCG. For best results, take a home pregnancy test after the first day of your missed period.
If you take the test twice and get different results, call your doctor. A blood test is a good idea to confirm the result.
If you have any other questions about the pregnancy test or the results, call your doctor or the telephone number listed with the test.
A faint line on a pregnancy test can be confusing. It can happen because it's very early in your pregnancy and your pregnancy hormone level is low, or because some tests have less bold lines than others. Experts say a faint line usually means you're pregnant. But see your doctor to be sure.
An evaporation line on a pregnancy test is a slight, colorless streak where the positive line should be. This might happen if you wait longer than suggested to read your test result, or if the test gets wet. It doesn't mean you're pregnant. It's a good idea to take another test to get accurate results.
What to Do After a Positive Pregnancy Test
When you get a positive pregnancy test result, contact your doctor for an appointment. They might want to give you a blood test to confirm you're pregnant. It's important to know as soon as possible if you're pregnant so you can start receiving prenatal care and making healthy lifestyle changes, if necessary.
- 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.
- Two main types of pregnancy tests are blood tests and urine tests.
- Urine home pregnancy tests, when taken correctly, are about 99% accurate. Blood tests are even more accurate.
- Urine home pregnancy tests are available in most drugstores, pharmacies, convenience stores, and grocery stores. Some dollar stores sell them. Some can be mail-ordered.
- If you get a positive pregnancy test result, contact your doctor for an appointment. Starting prenatal care as soon as possible is important for the health of you and your baby.
What are pregnancy symptoms in the first week? Most people have no symptoms the first week of pregnancy. Early signs usually appear weeks later. They include:
- missing a period
- nausea and vomiting
- breast tenderness and enlargement
- peeing more than usual, and at night
- cravings foods, not liking foods you usually like, and a sour or metallic taste in your mouth even when you’re not eating
Can a urinary tract infection (UTI) cause a false positive pregnancy test? It's rare but possible. Serious UTIs can cause your pee to have high levels of leukocytes and nitrite, which can cause a false positive pregnancy test result.
Can a pregnancy test be wrong? Yes. But at-home pregnancy tests, when taken according to their package directions, are about 99% accurate.
Why is my pregnancy test negative but I don't have a period? It's possible your negative test result isn't correct, but that would be very rare. You probably aren't pregnant.You might want to repeat the pregnancy test. You may have something else going on, or another medical issue, such as:
- Taking hormonal birth control
- Taking certain meds
- Experiencing perimenopause
- You have polycystic ovary syndrome (PCOS)
- You don't get enough sleep
- You have a lot of stress
- You have a thyroid condition
- You exercise too much
- You have recent weight changes
If you have any of these symptoms, get medical attention:
- Severe pain on one side of your belly
- Pain in one of your shoulders
- Bleeding from your vagina (that's not your period)
- Dizziness or fainting
- Nausea or vomiting