Home Pregnancy Tests: When to Take One, Accuracy and Results

By Dr. Gayatri Deshpande in Gynaecology & Obstetrics

Apr 24 , 2023 | 6 min read


What is a pregnancy test and how does it work?

A pregnancy test is commonly used to confirm or rule out pregnancy in women. The pregnancy test works by identifying the presence of the human chorionic gonadotropin hormone (hCG) in a woman’s urine or blood.

A positive result indicates pregnancy, whereas, if the result is negative, it means that there is no pregnancy.

What are the different types of pregnancy tests?

There are two types of pregnancy tests – urine tests and blood tests.

Blood Tests

  • These use a small sample of blood to detect the presence of hCG hormone.
  • Blood tests can detect even very small levels of hCG and can detect pregnancy quite early, within 7-10 days of conception.
  • They are expensive and are mostly used in doctor’s clinics to detect pregnancy.

There are 2 types of blood tests:

  • Qualitative hCG Test: This checks for the presence of hCG and determines whether a woman is pregnant or not.
  • Quantitative hCG Test: This test determines the amount of hCG in the blood. It can also help to find out if there are any problems in the pregnancy such as ectopic pregnancy, fall in hCG after a miscarriage, etc.

Urine Tests

  • Urine tests are common at-home tests that contain special chemical strips to check for hCG in the urine and determine pregnancy.
  • Urine tests can be purchased easily from a medical store and are quite inexpensive.
  • They are very easy to use and give results in just around 1-2 minutes.
  • The person must collect their urine in a container and place a few drops on the test step using an eyedropper, dip the test stick in the urine or hold it in the stream of urine to test for pregnancy.
  • Urine tests are most accurate when used 1-2 weeks after missing a period.

Do all at-home pregnancy tests work in the same manner?

At-home pregnancy tests detect hCG in the blood to confirm pregnancy, but testing methods of different tests may differ.

Most at-home pregnancy tests are reliable, but some may be more sensitive and deliver positive results more quickly than others. Nevertheless, it is advisable to wait until a period is missed to ensure more accurate results.

What are the benefits of using an at-home pregnancy test?

Some of the advantages of at-home pregnancy tests include:

  • These tests are available in all medical stores and they can be bought without a doctor’s prescription.
  • They are quite inexpensive and very easy to use.
  • They are very convenient to use in the comfort of your home.
  • They provide results very quickly, in just 1-2 minutes and the results are very easy to read.
  • They are fairly reliable and provide quick and accurate results (with around a 98%-99% accuracy rate) when done correctly.
  • They can be helpful to start or stop any medications and also make any necessary prenatal lifestyle changes.

When to take an at-home pregnancy test?

At-home pregnancy tests claim to determine pregnancy as early as the first day of a missed period or even earlier.

However, taking the test too soon can lead to a false negative result because the body produces hCG, the pregnancy hormone, only after implantation of the fertilized egg in the uterus.

The accuracy of the pregnancy test can be affected by the timing of ovulation and irregular menstrual cycles, making it difficult to ascertain when a period should start. It is recommended to wait until a missed period because then, the test can provide a more accurate result.

What time to take a home pregnancy test?

For maximum accuracy, it is advised to take a pregnancy test using the first-morning urine.

However, nowadays, tests are quite sensitive and can detect hCG at any time of the day. It is best to wait for 3 hours at least since the last urination before taking the test. It is also recommended to take two tests to confirm the results.

Where to get an at-home pregnancy test?

At-home pregnancy tests are quite inexpensive and can be easily purchased from a medical store over the counter.

How to use an at-home pregnancy test?

1. Pregnancy tests can be used in different ways:

  • By putting drops of urine on the test strip
  • By dipping the test into the urine
  • By holding the test stick in the urine stream

2. Wait for the recommended time (usually about 2 minutes) before checking the result.

3. The result can appear as 1 or 2 lines, plus or minus signs or the words yes/no or pregnant/not pregnant.

4. Check the control indicator to ensure that the test is working.

5. Check the expiration of the pregnancy test and follow the usage instructions carefully.

Are home pregnancy tests accurate?

When used correctly, most at-home pregnancy tests are around 99% accurate. These tests have the highest accuracy when used after missing a period.

While a positive result means that the person is pregnant, a negative result may be a false negative. It is advisable to retake the test a week after missing the period to reconfirm the results.

What do pregnancy test results mean?

Positive pregnancy test results

  • Whether the line, symbol or colour is dark or light, a positive result indicates that the woman is pregnant.
  • False positive results are quite uncommon. But in a rare case that the result is false positive, it means that the person is not pregnant although the test says that they are.
  • False positive results usually occur if there is protein or blood in the urine. False positive results can also be caused due to particular drugs like anticonvulsants, tranquilizers, fertility drugs or hypnotics.

Negative pregnancy test results

Negative results on a pregnancy test mean that the person is not pregnant. However, the pregnancy test may give a false negative result in the following instances:

  • If the test has been used too soon
  • If the test is used incorrectly
  • If the pregnancy test is past the expiration date
  • If the urine is too diluted due to drinking a lot of water or fluids before taking the test
  • If the person is taking particular medications such as antihistamines or diuretics

If there is any uncertainty about the pregnancy result or if the person suspects that they may be pregnant despite getting a negative result, it is recommended to retake the test. In such cases, it is advisable to retake the test after a week.

Can medications affect pregnancy test results?

Most medications including birth control pills and antibiotics do not affect home pregnancy tests, but fertility drugs or those containing hCG can impact results.

Can a positive pregnancy test result be wrong?

Although it is very rare, a home pregnancy test may give a false positive result when the person is not pregnant.

This may occur if a woman has had a recent miscarriage or takes a test soon after taking fertility medication containing hCG. False positive results may also occur due to menopause or ovary issues.

Can a negative pregnancy test result be wrong?

Yes, a home pregnancy test can give a negative result even if the person is pregnant. This is called a false negative, which can occur under the following conditions:

Taking the test too early

A false negative result may result if the pregnancy test is taken too early. It is best to wait a day after a missed period for accurate results.

Checking the results before the time

Wait for the time specified in the pregnancy test before checking the result. Checking earlier may give an inaccurate or false negative result.

Taking the test later in the day

For the most accurate results, it is recommended to take the pregnancy test in the morning when the urine is most concentrated.

Which kind of pregnancy test can help to detect pregnancy the earliest?

A blood test can detect pregnancy earlier than a urine test because it is more sensitive and can detect even smaller levels of hCG.

Will an ectopic pregnancy be detected by a pregnancy test?

Yes, an ectopic pregnancy can be detected by a pregnancy test because of the production of hCG.