Can You Reuse a Pregnancy Test?
By OBGYN Dr. Kenosha Gleaton
Taking a pregnancy test can be an exciting, stressful, or sometimes upsetting experience. Understanding exactly how pregnancy tests work, how to use them properly, and what types of test options there are is key. Being informed can give you peace of mind and help you get the clear answer you need when the time is right. So, here’s an overview of pregnancy tests.
How Do Pregnancy Tests Work?
At-home pregnancy tests work by detecting a certain hormone in your urine. If there is a high enough concentration of this hormone, a positive result will appear. The hormone that is being detected is called human Chorionic Gonadotropin (hCG), also known as the pregnancy hormone.  hCG is the first detectable sign of pregnancy that the body will begin to produce as soon as an embryo implants into the uterine wall.  Learn about implantation bleeding →
How to Use a Pregnancy Test
While most pregnancy tests have very similar instructions, it’s important to follow the steps shown on the packaging for best results. For Natalist Midstream Pregnancy Tests, the steps are as follows:
- Find a well-lit bathroom with a clean, flat surface.
- Unwrap one pregnancy test, remove the cap, and place the cap nearby (don’t throw it away).
- Sit on the toilet and get the test in place. Hold the test handle and point the absorbent tip downward.
- Pee directly on the absorbent tip (below the arrow) until it’s completely saturated. This can take about five seconds. Be careful not to pee above the arrow, on the test window, or on your fingers.
- Keep the absorbent tip pointing downwards while you put the cap back on.
- Lay the test on a flat surface with the result window facing up. Wait five minutes to look at results, and make sure to read results within 15 minutes.
It’s often recommended to test first thing in the morning when urine is the most concentrated, but you can test at any time of day. Make sure that you see a control line to ensure you have a valid test. If your test is missing the control line, use a different test.
Types of Pregnancy Tests
There are many different types of pregnancy tests, including midstream tests, test strips, digital tests, urine tests, blood tests, etc. Blood tests can be done at a provider’s office while urine tests are often taken at home.  Pregnancy tests that have a screen, showing you either a smiley face, “yes/no” “pregnant/not pregnant”, etc. are called digital tests. Analog tests can be midstream, cassette tests, or test strips that are dipped in a cup of urine. Analog tests will show you lines rather than a screen.  Learn about the differences between digital and analog tests.
Can You Reuse a Pregnancy Test?
No, you should never reuse a pregnancy test.  Once a test has been used once, it can only provide a valid result for about 15 minutes. Beyond this time frame, there is a risk of evaporation lines forming or invalid results showing up. An evaporation line is a faint mark on a pregnancy test that is caused by a test getting wet or urine evaporating. An evaporation line can easily be mistaken as a positive result.
If you believe you made a mistake when taking a pregnancy test, or you’re confused about your results, you should take a new test and speak to a healthcare provider. In some cases, it may be best to wait another day, as hCG doubles almost daily during early pregnancy and may increase your chances of getting a dark positive result.  Avoid the stress of going out to buy a new test and get Natalist tests in bulk instead. Or you can opt for Early Pregnancy Test Strips, which contain 15 test strips!
Can You Reuse a Negative Pregnancy Test?
No, reusing a pregnancy test is never a good idea, regardless of if you received a positive or negative result. Pregnancy tests are designed to be used once, and reusing a test is not likely to give you an accurate result.  Instead, it’s best to use a completely new test. If you did receive a negative test but feel as though this was a mistake, wait and test again tomorrow morning or see a healthcare provider.
Can You Use an Expired Pregnancy Test?
Believe it or not, pregnancy tests do expire.  Most pregnancy tests will have an expiration date that is a few years after it is produced. What makes a pregnancy test expire is the antibodies and chemicals that react to the hCG in urine, causing a positive result. [1-2] If a test is expired, it’s possible that these antibodies may be broken down, unable to accurately detect pregnancy and causing an invalid result. If you notice your test is expired, you should purchase a new box of tests to avoid getting a false result.
Pregnancy tests are an extremely useful tool for getting clear answers about your reproductive health in the comfort of your own home. There is a long list of options when searching for pregnancy tests, from digital tests to analog test strips. Just make sure that you are following the instructions exactly to get an accurate result. You should only ever use a pregnancy test once. Avoid using expired tests or reusing tests. Natalist is proud to offer sensitive, early-result pregnancy tests in two different forms. You can even bundle and save when you get a hormone fertility test or ovulation tests as well. Learn more about testing for pregnancy on the Natalist blog.
- Eskandar MA, Al-Shahrani M, Shaamash A, El-Emain M, Al-Ahmad M, Payodon B. Early Maternal Serum β-human Chorionic Gonadotropin Measurements After ICSI in the Prediction of Long-term Pregnancy Outcomes: A Retrospective Cohort Analysis. J Clin Med Res. 2011;3(1):30-35. doi:10.4021/jocmr477e
- Gnoth C, Johnson S. Strips of Hope: Accuracy of Home Pregnancy Tests and New Developments. Geburtshilfe Frauenheilkd. 2014;74(7):661-669. doi:10.1055/s-0034-1368589
- Guidance for Over-the-Counter (OTC) Human Chorionic Gonadotropin (hCG) 510(k)s - Guidance for Industry and FDA Reviewers/Staff. Center for Devices and Radiological Health, Office of Product Evaluation and Quality. FDA-2020-D-0957. July 2000. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-over-counter-otc-human-chorionic-gonadotropin-hcg-510ks-guidance-industry-and-fda