How accurate are home pregnancy tests?

Home pregnancy tests are accurate as long as you follow the instructions correctly.

A positive test result is almost certainly correct. However, a negative test result is less reliable. The result may not be reliable if you:

  • don't follow the instructions properly
  • take the test too early

Some medications can also affect the results.  

You can buy home pregnancy tests at most pharmacies and most large supermarkets.

Carrying out a test

When you become pregnant, your body produces the pregnancy hormone, human chorionic gonadotrophin (HCG). Home pregnancy tests detect HCG in your urine.

Make sure you read the instructions carefully before you do the test, because pregnancy tests use different methods and display the results in different ways. You can take the test from the first day of your missed period. Tests carried out earlier than this are not always accurate. If your periods are irregular, you may not be sure when this is. For more information, see How soon can I do a pregnancy test?

Check the instructions to make sure you can do the test at any time of day. It’s usually best (but not essential) to take the test first thing in the morning as your urine will have the biggest concentration of hormones then.

Avoid drinking too much fluid beforehand, as this can dilute the level of HCG in your urine.

Positive test results

If the test result is positive, you're almost certainly pregnant. Contact your GP as soon as possible. Because home pregnancy tests are so accurate, they may not repeat the test.

If you want to continue with your pregnancy, a healthcare professional can organise your antenatal care. If you're not sure about if you want to continue with the pregnancy, you can find more information about your options in Am I pregnant?

If you want to know when the baby is due, you can use the pregnancy due date calculator.

Negative test results

If the test result is negative, you may not be pregnant. However, negative results are less reliable. For example, if you do a pregnancy test too early, you could be pregnant, but there may not be enough HCG in your body to give a positive test result.

Pregnancy tests vary in their sensitivity (how soon they can detect HCG and what level of HCG needs to be present). You can find information on the packaging about how sensitive your test is.

If you still think you’re pregnant after a negative result, wait a week and try again or make an appointment to see your GP.

Medications

Some medications can affect test results, including:

  • promethazine: used to treat conditions such as allergies
  • medicines used to treat Parkinson’s disease 
  • sleeping tablets (hypnotics) 
  • tranquillisers 
  • diuretics (medicines that increase the amount of urine produced): used to treat conditions such as heart failure
  • anticonvulsants (medicines that prevent seizures or fits): used to treat conditions such as epilepsy  
  • medicines used for infertility 

If you’re taking any medication, the patient information leaflet that comes with it will tell you whether it affects test results.

Early miscarriage

If your first pregnancy test result is positive, but a later one is negative or your period arrives, it's possible you've had an early miscarriage. Contact your GP or midwife for advice.

Read answers to more questions about pregnancy.

Further information:

Page last reviewed: 31/05/2012

Next review due: 31/05/2014