Home Pregnancy Test

If you think you are pregnant, you may want to test yourself at home with a home pregnancy test. You can buy test kits at a drug store without a prescription. Home use kits measure a hormone called human chorionic gonadotropin (hCG) in your urine. However, these tests are qualitative, the results are either positive or negative for pregnancy.

The most sensitive test of pregnancy is best performed by a laboratory using a sample of your blood. These tests not only detect hCG but also can indicate the amount (quantitative tests) of the hormone, which doubles every 2-3 days during the first several weeks of pregnancy. These more sensitive tests can tell how long you have been pregnant and even detect possible problems with the pregnancy. Your health care provider can perform this test.

Initially, many women prefer the privacy, convenience, and quick results from home test kits. Home pregnancy tests are not as accurate as blood tests done by your health care provider. They also cannot determine if your pregnancy is developing as expected.

The hormone hCG may be detected in urine about 2 weeks after conception (when the egg is fertilized by sperm).

With the home test kit, you place a drop of your urine on a prepared chemical strip. It usually takes 1 or 2 minutes for the strip to indicate the result.

To get the best results from your home test kit, follow the instructions that come with the kit. 

• Read the label and instructions carefully:  Review all instructions and pictures to make sure you understand how to perform the test. The instructions will tell you the following information:
  
  
  • What the test is for and what it is not for
    
    
  • How to collect and store your urine sample
    
    
  • When and how to run the test, including timing instructions
    
    
  • How to interpret the test results
    
    
  • What might interfere with the test results
    
    
  • The manufacturer's phone number if you have questions
    
    
• Only use tests regulated by FDA:  Ask the pharmacist or check the FDA database at How Can You Know if a Home Use Test Is Regulated by the FDA. If a test is not regulated by FDA, the US government has not determined the product to be reasonably safe or effective. 
  
  
• Follow all instructions:  You must follow all test instructions to get an accurate result. Most home tests require specific timing, materials, and sample amounts. You should also check the expiration dates and storage conditions before performing a test to make sure the components still work correctly.
  
  
• Keep good records of your testing.
  
  
• Call the 800 telephone number listed on your home use test if you have any questions.
  
  
• When in doubt, contact your health care provider:  All tests can give false results (meaning the test indicates you are pregnant but you may not be, or the test says you are not pregnant and you are). You should see your doctor if you believe your test results are wrong or to confirm the result.

Don't change medications or dosages based on a home test without talking to your doctor.

For most home pregnancy tests, you either hold a test strip in your urine stream as you urinate into the toilet or you collect your urine in a clean cup and dip your test strip into the cup. If you are pregnant, most test strips produce a colored line, but this will depend on the brand you purchased. Read directions carefully to interpret the results. Read the instructions for the test you bought and follow them carefully. Make sure you know how to get good results. The test usually takes only a few minutes.

• Some tests are able to detect low levels of hCG, indicating pregnancy. For the most reliable results, test 1-2 weeks after you miss your period. There are some tests for sale that are sensitive enough to show you are pregnant before you miss your period.
  
  
• You can improve your chances for an accurate result by using your first morning urine for the test. This urine has accumulated in your bladder overnight. If you are pregnant, it will have more hCG in it than urine collected later in the day.
  
  
• If you think you are pregnant, but your first test was negative, you can take the test again after several days. Because the amount of hCG increases rapidly when you are pregnant, you may get a positive test on later days. Some test kits come with more than one test in them to allow you to repeat the test.
  
  
• The home pregnancy test and the urine pregnancy test used by your health care provider are similar. Both can detect hCG, but your provider is probably more experienced in running the test. The doctor may follow up with a more sensitive blood test to see if you are pregnant and may conduct a physical exam for a more reliable result.

Types of home use test kits

• The most common kits use a test strip or dipstick, which you hold in your urine as you urinate into the toilet. With other tests you may urinate into a cup and dip the test strip into the cup. A section of the strip changes color if hCG is detected – showing that you are probably pregnant.
  
  
• Some kits contain a urine collection cup with a built-in testing device. You either put a few drops of urine into the device or immerse the device into urine in a cup. Again, a test strip changes color, showing positive or negative for pregnancy.

Other, less frequently used test kits require you to mix urine samples with powders or liquids.  The chemical reaction produced shows a color change, which you compare to a chart for interpretation.

If you are pregnant, you will want to follow up with your health care provider to confirm the result and begin prenatal care. If you are on any prescription medications, do not stop taking them without first consulting your health care provider.

There are no medical risks associated with testing for pregnancy.

You may obtain inaccurate results that are either falsely positive or falsely negative. Errors can result from how you collected the sample, being too early in the pregnancy to detect hormone changes, the time of day you collected the sample  (urine sampled first thing in the morning is best), or effects of medications you take.

One study showed that women had difficulty following the instructions on the package insert. In this study, many positive-for-pregnancy samples showed negative results (inaccurately). 

The accuracy of the home pregnancy test depends on how well you follow the instructions and interpret the results. If you mishandle or misunderstand the test kit, you may get the wrong results.

You may be testing yourself too early in your cycle. So, you could be pregnant but not yet producing enough hCG to show up on the home use test. This could be a particular problem if you have irregular periods or miscalculate the date of your last period.

If your period is late and you suspect you may be pregnant, wait 7-10 days before trying the home pregnancy test. If the test is negative, wait a few more days. If you still don't menstruate, try the test again. If you still test negative and your periods do not return to normal, see your health care provider.

If your symptoms don't seem to agree with your test results, or if your test or device does not seem to be working properly, you can report it to FDA's MedWatch program at the US Food and Drug Administration, MedWatch.

If you want to notify the Office of In Vitro Diagnostic Device Evaluation and Safety of the US Food and Drug Administration directly of a problem with a home use test, send an email to fdalabtest@cdrh.fda.gov.

|Web Links|

American Association for Clinical Chemistry, Lab Tests Online, hCG Test

US Food and Drug Administration, Office of In Vitro Diagnostic Device Evaluation and Safety (OIVD)

MEDLINEplus, Pregnancy test

Planned Parenthood Federation of America

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Author: Omnia M Samra, MD, Clinical Instructor, Department of Obstetrics and Gynecology, Medical College of Pennsylvania/Hahnemann University.

Editors: Bryan D Cowan, MD, Director, Division of Reproductive Endocrinology, Professor, Department of Obstetrics and Gynecology, University of Mississippi College of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, ; Lee P Shulman, MD, Professor of Obstetrics and Gynecology, Head, Section of Reproductive Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.